DOI: https://doi.org/10.21203/rs.3.rs-2104778/v1
Therapeutic exercise exerts positive effects by mitigating or reducing the motor or cognitive changes that people with Down syndrome undergo throughout their life. There are no updated systematic reviews that integrate the evidence available in way that facilitates decision-making for physical rehabilitation teams. This study aimed to assess the effect of different types of physical exercise on the motor function of adults with Down syndrome.
We conducted a systematic review and meta-analysis of randomized clinical trials and quasi-experimental studies. The literature search was performed between September 2020 and June 2021 using the PubMed, SCIELO, Epistemonikos, and Lilacs databases. Studies were selected according to pre-determined inclusion and exclusion criteria. The risk-of-bias assessment was performed using the risk-of-bias rating tool. Risk-of-bias assessment and meta-analyses were performed using the RevMan software package.
Water aerobic exercise significantly increased isometric push-up strength time (mean difference MD = 24.00 [95% CI = 2.66–45.35]; P = 0.03), while combined exercise significantly increased muscle strength both in the upper limbs (MD = 11.93 [95% CI = 4.72–19.14]; P = 0.001) and lower limbs (MD = 18.47 [95% CI = 2.34–34.60]; P = 0.02). Aerobic exercise improved spatiotemporal gait parameters. Aerobic exercise in an aquatic environment and continuous and interval training improved six-minute walk (MD = 43.21 [95% CI = 0.84–85.57]; P = 0.05). The certainty assessment revealed low certainty for all outcomes.
There was low certainty of evidence for the outcomes proposed in this review. However, therapeutic exercise was shown to be effective in improving muscle strength and gait functionality.
Down syndrome (DS) is a medical condition caused by a genetic abnormality where chromosome 21 [1] is either partially or completely duplicated. It is the most common and prevalent genetic neurological disorder associated with intellectual disability and motor disorders characterized by hypotonia, ligamentous laxity, and limited muscle strength [2], in addition to other cardiorespiratory, gastrointestinal, and immunological comorbidities [3].
The motor changes in balance, strength, resistance, and mobility [2] caused by DS have a direct effect on motor functions, defined as the ability or capacity to learn, maintain, coordinate, and assume voluntary control of postures and movement patterns [4]. Therefore, DS affects quality of life and the ability to perform activities of daily living (ADL), thus increasing the dependency on other individuals and the adoption of a sedentary lifestyle in many cases [5].
Therefore, individuals with DS require therapeutic interventions, especially rehabilitation, to improve their motor skills. Therapeutic exercise is included within these interventions, which the World Health Organization defines as “a variation of physical activity, aimed at reaching a pre-established goal, which is generally the improvement or maintenance of physical fitness or of the health condition” [6]. Furthermore, exercise is characterized as being planned and repetitive. In other words, it is performed regularly [6] and divided into different types: aerobic exercise, where large muscle groups are exercised, thus improving cardiovascular capacity; strength exercises; flexibility or stretching exercises; and neuromuscular exercises, including proprioception, balance, and agility exercises [7].
Scientific evidence of the effects of exercise in individuals with DS is extensive in this regard. Multiple interventions have been identified in the literature that evaluate the effectiveness of exercise in water [1, 2], progressive resistance exercise [8, 9], continuous aerobic exercise [5, 10–12], specific modalities such as Nordic walking [13], and combined exercise. In other words, simultaneous aerobic and resistance training [14–16] have an impact on different motor function outcomes, such as aerobic and functional capacity [2, 5], dynamic balance, muscular strength and endurance [1, 8, 10, 14–16], and gait [13].
However, the many types of therapeutic exercises available in the literature as well as the many motor function outcomes against which the effectiveness of these types of exercise is measured impede rehabilitation teams’ decision-making when attempting to identify the type of exercise that, according to its prescription, is the most effective in improving these motor function outcomes.
Although there is a substantial amount of evidence on the effect of exercise in adults with DS, there is no accumulation of this evidence that accounts for the effect of different types of therapeutic exercise, mode of application, and in general, the prescription parameters of effective interventions. The integration of available evidence will facilitate decision-making for physical rehabilitation teams. This study therefore aimed to consolidate the information available and compare the effects of different types of physical exercise on the motor function of adults with DS.
This review was conducted in accordance with Cochrane Handbook of Systematic Reviews of Interventions [17] and the recommendations of the methodology proposed in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines[18]. This analysis was prospectively registered on Open Science Framework (OSF) and it is available in https://doi.org/10.17605/OSF.IO/MRKN2. Ethical and internal review board approval was not required because no human or animal subjects were involved.
Studies
Experimental studies such as randomized or quasi-experimental clinical trials were included. Studies that included the population in this review as well as populations with other characteristics, and studies whose results for participants with DS were not presented separately, were excluded. Studies that did not include at least one of the outcomes proposed for this review were excluded.
Participants
Individuals with DS aged 18 years or older.
Interventions
Application of any type of therapeutic exercise—either strength or resistance, aerobic, or neuromuscular exercise—with specific prescription parameters such as intensity, duration, and frequency.
Outcome measures
The outcomes prioritized in this review were as follows
Primary: Strength, defined as the ability of a muscle group to develop contraction against resistance [19]; balance or equilibrium, understood as the ability to maintain the body’s stability on each side of the axis [20]; and gait variables, defined as bipedal walking used to move from one place to another with minimal effort and energy consumption [20].
Secondary: Coordination, defined as the ability to execute and control movements [20]; posture, defined as the alignment of body segments during movement or a sustained situation [20]; and functional tasks, such as climbing stairs.
The literature search was performed using the PubMed, SCIELO, Epistemonikos, and Lilacs databases with the following keywords: “Down Syndrome,” “trisomy 21,” “syndrome, down,” “mongolism,” “trisomy G,” “down’s Syndrome,” “adult,” “exercise,” “therapeutic exercise,” “physiotherapy,” “physical,” “physical therapy,” “training,” “neuromuscular exercise,” “endurance training,” “motion therapy,” “muscle stretching exercises,” “plyometric exercise,” “resistance training,” “motor function,” “functionality,” “balance,” “posture,” “coordination,” “gait,” “strength,” “basic physical abilities,” “speed,” “resistance,” “strength,” “skill,” “flexibility,” “agility,” “Down syndrome,” “physiotherapy,” “balance,” “posture,” “strength,” and “gait.”
The search was conducted from September 2020 to June 2021 and no filters by language or publication date were applied.
Other sources
The search was performed through the L·OVE platform (Living Overview of Evidence) in English in the DS section [21]. Additionally, other sources of evidence were consulted to allow for the identification and analysis of published or unpublished literature (gray literature) that had not been detected through the systematic search. Manual searches were performed in reference lists of documents found through the search and in specialized journals on the subject. Furthermore, to review the studies included in them, the Epistemonikos database was searched for previous systematic reviews on this topic. An evidence matrix was constructed based on this information, which automatically lists the systematic reviews that share at least one study included as well as all the studies included in each of these reviews [22].
Study selection
This was performed by two reviewers independently applying the selection criteria (MMM, YVC). Duplicate studies were initially merged into a bibliographic reference manager, followed by screening through the review of titles and abstracts to identify studies that included the population of interest for the present review, therapeutic exercise intervention, and at least one of the motor function outcomes. Subsequently, the full texts of the selected studies were retrieved, and after a comprehensive reading, studies were excluded based on their design, the population included, or because they did not include at least one of the motor function outcomes. A third reviewer (ERG) intervened to define whether or not studies for which there was no agreement should be included in this review.
Data extraction and management
This was conducted by two reviewers independently (MMM, YVC) in an Excel file. The following items were extracted: year of publication and authors; title; characteristics of participants such as age, sex, and number of participants per group; characteristics of the interventions applied, such as the type and mode of exercise, with their prescription of intensity, duration, and frequency; outcomes evaluated with their respective measuring instruments; and the results obtained by variable and group.
Risk-of-bias assessment
This was performed using the risk-of-bias (RoB) tool [17] based on seven domains, namely, sequence generation, allocation concealment, blinding of participants and personnel, blinding of outcome assessors, incomplete outcome data, selective outcome reporting, and “other aspects.” Each of these domains was assigned a rating of “low risk,” “high risk,” or “unclear risk.” The risk-of-bias assessment was performed using the RevMan 5.4 software [23].
The selected body of evidence was assessed according to the prioritized outcomes. Each outcome described the population’s features; parameters of the interventions, including the exercise mode applied, frequency, intensity, and duration of the interventions applied in the said studies; and the quantitative results achieved with their level of significance (Table 1). The data were synthesized on a Microsoft Excel base, extracting data from the population’s features, randomization methods, outcome measures, duration of follow-up, and assessment methods from each study. The meta-analysis considered direct comparisons between the experimental group that performed the interventions (aerobic exercise and resistance exercise) and a control group that performed educational activities, recreational activities, or continuity with ADL or interventions other than those of interest for this review.
Averages and standard deviations of the data available from the selected studies were extracted from the prioritized outcomes included in the studies. When the studies reported standard errors of the mean, the standard deviations were obtained by multiplying standard errors of the mean by the square root of the sample size. Standardized mean differences (MD) and 95% confidence intervals (95% CI) were calculated to combine the results of the studies using different measures for the same concept or of studies presenting variability in its features.
Heterogeneity between trials was assessed using the chi-squared test, with a p value of < 0.05 considered statistically significant after due consideration of the value of I2 Heterogeneity was reported as low (I2 = 0–25%), moderate (I2 = 26–50%), or high (I2 > 50%) [24, 25]. The results were combined using the random effects model and the 95% CI was calculated. All data analysis were performed using the RevMan 5 software [23]
Assessment of the certainty of evidence
This was performed using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) system [17] for each outcome. This system specifies four levels of quality evidence: “High,” “Moderate,” “Low,” and “Very Low.” The level is determined by considering the risk of bias in the study, inconsistency, direction of evidence, precision of an effect estimate, and other considerations that include publication bias, whether or not the effect is large, the existence of confounding factors, and the dose–response gradient. These variables, except for “other considerations,” were evaluated on a three-level scale: “not serious,” “serious,” and “very serious.” For “other considerations,” the publication bias scale was classified as “not detected” or “strong suspicion”; large effect was graded as “no,” “large,” or “very large”; confounders were graded as “no,” “will reduce the demonstrated effect,” or “suggests a spurious effect”; and the dose–response gradient was classified as “yes” or “no.”
The electronic search yielded 532 studies, and 190 studies were obtained from other sources to yield a total of 722. Of these, 127 studies were excluded owing to duplication and 547 were excluded after the review by titles and abstracts. In total, 48 studies were assessed in full text, of which 36 were excluded because they did not meet the eligibility criteria, mainly the study design, and because they did not include at least one of the outcomes prioritized in this review. Thus, only 12 studies met the eligibility criteria for the qualitative synthesis and 5 were included in the meta-analyses. This information is presented in a flowchart following the PRISMA model (Fig. 1).
Table 1 shows that the studies selected for this review included a total of 332 participants aged 18–65 years. Of the 12 studies, 7 [1, 2, 5, 13, 15, 16, 26] included the population aged 21–42 years, with only 2 [10, 27] including the population aged 60 years and older, and 4 [8, 9, 30, 31] included the population aged 18–20 years. The study with the smallest sample was the one by Davis and Sinning [28], with 18 participants, while that with the largest sample was the study by Rimmer et al. [16], with 52 participants.
Sequence generation
Six articles presented a high bias because there was no randomization [26], and nonrandomized categorization methods were used to assign participants according to their place of residence [2], availability to provide a monitored intervention in each residence [9], or the characteristics of each participant [13, 15, 28]. Moreover, one article [16] had an unclear bias as randomization was performed but the method was not described.
Allocation concealment
Half of the selected studies, i.e., six [1, 2, 5, 10, 13, 16], had unclear bias. The allocation was not concealed, so the bias was classified as high in the case of Cowley et al. [9].
Blinding of participants and personnel
Seven studies [1, 8–10, 13, 15, 27] had unclear bias. Four studies had a high bias rating because one of them was performed by the primary investigator [2], thus eliminating the possibility of personnel blinding. In another study, participants were notified of the group they belonged to with no mention of personnel blinding [16], and finally, in Aguiar et al. [25] and Davis [28] the participants were not blinded.
Blinding of outcome assessors
Seven studies [1, 2, 13, 15, 16, 23, 27] had unclear bias. Of the remaining studies, three [5, 8, 10] had low bias as blinding was reported. The other two studies were rated as having high risk of bias due to nonblinding of assessors.
Incomplete outcome data
Eight of the studies included in this review [1, 2, 5, 8, 10, 13, 27, 28] were classified as having low risk of bias in this domain because there was complete data management, including exclusions and dropouts for the respective reasons. The other studies [9, 15, 16, 26] had unclear risk of bias.
Selective outcome reporting
Only two studies [10, 13] obtained a high risk of bias rating in this domain because data from the control group, whose changes were significant, were omitted. The remaining studies [1, 2, 5, 8, 9, 15, 16, 26–28] had low risk of bias because they reported all the prespecified data.
Other aspects
The other sources of bias were only identified in three studies [1, 5, 8]. Two of them were classified as having an unclear risk of bias [1, 5] as they did not specify participants’ level of intellectual disability. The other study [8] presented a high risk of bias due to possible confounding bias because eight of the participants included performed manual tasks that involved skills or patterns that the study assessed within its outcomes and, in turn, included in its intervention. In other words, these participants also applied these patterns in their jobs in addition to receiving the intervention proposed by the study, therefore their results may be derived both from the intervention and from each participant’s job.
Figures 2 and 3 summarize the information on bias risk domains.
This outcome was the most frequently reported within the studies included. The interventions addressed aerobic exercise in water [1, 2], continuous and interval aerobic exercise [5], aerobic exercise [10], progressive resistance exercise [8, 9], resistance exercise [28], and combined exercise [15, 16]. The duration of the interventions was between 6 [2] and 25 weeks [10] with frequencies ranging from two [8, 9] to three times a week [1, 2, 5, 10, 15, 16, 28] Table 1.
Results were found in favor of interventions for abdominal strength [1, 2], increasing the number of abdominal push-ups performed ( Appendix 1, Fig. 4). However, these results were not significant (MD = 10.73 [95% CI = − 3.91–25.36]; P = 0.15). Significant results were identified (MD = 24.00 [95% CI = 2.66–45.35]; P = 0.03) regarding the strength of the upper limbs [1, 2], where the time of maintaining the isometric flexion position of the arms was increased (push-up) (Fig. 4). A trend was found in favor of the experimental groups in the lower limb test (Appendix 1, Fig. 5), where the number of times to get up and sit down on a chair in 30 seconds was increased [1, 2, 5]. However, there were no significant results after these interventions (MD = 0.39 [95% CI = − 0.48–1.27]; P = 0.38).
Finally, significant results were found in the strength of both the upper (MD = 11.93 [95% CI = 4.72–19.14]; P = 0.001) and lower limbs (MD = 18.47 [95% CI = 2.34–34.60]; P = 0.02), regarding the interventions of combined exercise [16] and progressive resistance exercise [8] against the muscular strength of the upper and lower limbs (Appendix 1, Fig. 6), with increases in the 1-repetition maximum (RM) leg press and 12-RM chest press protocols.
Interventions used to improve balance included aerobic exercise in aquatic environment [1, 2] and in the terrestrial environment [10], continuous and interval aerobic exercise [5], and combined exercise [27]. These interventions lasted between 6 [2] and 25 weeks [10], with a frequency of three times per week Table 1.
Both static and dynamic balances were assessed. For static balance (Appendix 1, Fig. 7), Boer [1] and Boer and de Beer [2] observed improvements in time maintaining balance on one leg and in the number of consecutive steps on a balance beam; however, these improvements were not significant (MD = 0.43 [95% CI = − 1.55–2.41]; P = 0.67). Regarding dynamic balance (Appendix 1, Fig. 7), the improvements were not significant either (MD = 0.55 [95% CI = − 0.63–1.72]; P = 0.36).
Two studies evaluated the effectiveness of their gait interventions [9, 13]. The interventions applied were aerobic exercise through Nordic walking [13] and progressive resistance exercise [9]. The interventions lasted 10 weeks with a frequency of two [9] to three times per week [13]. Cowley et al. [9] found no significant differences in gait speed after their intervention. Conversely, Skiba et al. [13] found an improvement in the space-time parameters, angular changes of the limbs, and mean values of the angular deviations at the joints.
The interventions applied included aerobic exercise in an aquatic environment [1, 2], continuous and interval aerobic exercise [5], progressive resistance exercise [8, 9], and combined exercise [27]. The durations ranged from 6 [2] to 12 weeks [5], with frequencies ranging from two times [8, 9] to three times per week [1, 2, 5, 27]. The measuring instruments are shown in Table 1.
It was found that the interventions applied for this outcome [1, 2, 5] had significant results (MD = 43.21 [95% CI = 0.84,85.57]; P = 0.05) in the 6-minute walk performance (Appendix 1, Fig. 8). Similarly, the time to perform the test after the interventions was reduced in the 8-foot up and go test [1, 2, 5]. However, these results were not significant (MD = − 0.34 [95% CI = − 0.89–0.21]; P = 0.22) (Appendix 1, Fig. 9).
It was found that the certainty of evidence was low for all studies because some had a high risk of bias in the random sequence generation and an unclear risk in blinding. In other studies, the confidence intervals were wide and exceeded the no effect line and some had unclear risk of bias in 4 out of 7 criteria.
This systematic review assessed the effect of different types of physical exercise on the motor function of adults with DS. Among the types of exercise identified in the literature reviewed to improve muscle strength, balance, and gait are aerobic exercise in different modes, such as aquatic, judo, bicycle, and walking. Modes with mechanotherapy equipment were included within the muscle strength exercise, and endless treadmills and elliptical bike were mainly included within the cardiovascular resistance exercises.
Physical exercise is important throughout life because it improves the health [29]. Physical exercise also has a therapeutic objective for individuals with DS as they may require exercise-based clinical interventions throughout their life to improve physical abilities, such as muscle strength, flexibility, and balance [30]. These diminished physical abilities in individuals with DS hinder the performance of ADL and impact their quality of life [31].
Three studies included muscle strength as an outcome. Aguiar et al. [26] found no differences between the initial and final measurements after a judo training program, while Boer [1] and Boer and de Beer [2] observed an increase in muscle strength with aquatic aerobic exercise, as did Boer and Moss [5] with a bike or treadmill workout. However, the impact of aerobic exercise on increasing muscle strength remains controversial [32]. The American College of Sports Medicine recommends combining the intensity, volume, and frequency of training to improve muscle strength in young, middle-aged, and older populations and to optimize muscle hypertrophy and strength gains [33]. Vigorous training intensity and/or high training frequency, however, may be difficult to include in a training program for individuals with DS owing to their characteristic comorbidities as well as in older adults.
Studies in other populations have reported improvements in muscle hypertrophy, and thus, in muscle strength among younger and older adults after engaging in a single type and mode of physical exercise that includes walking [34, 35] and riding a bicycle [36, 37], which is consistent with the findings of this review.
Only aerobic exercise was used to improve balance in adults with DS in aquatic mode [2], with treadmill [10] and bicycle [5], and differences were reported only for the intervention in aquatic mode. Earlier studies have shown the mechanisms underlying this type of exercise that can improve balance, considering that the aquatic environment can stimulate an increase in the strategies and postural adjustments necessary for the execution of different movements [38]. This improves the quality of motor function by improving muscle strength and balance [39].
There were no differences in functional fitness between aerobic exercise in the aquatic or terrestrial modes. Studies including resistance exercise did not assess this outcome. Functional fitness is a construct in which all the physical abilities, which were also included as outcomes in this review, including muscle strength, balance, and posture, and other outcomes, which were not prioritized in this review, such as flexibility and mobility, were included. Physical exercise should enhance all of these abilities for an impact on functional fitness [40].
Among the limitations of this study, we can mention the methodological limitations of the studies included. All the studies included met at least one of the criteria for unclear risk of bias and 9 out of 12 studies met at least one criterion for high risk of bias. This is consistent with the certainty of evidence for each of the outcomes proposed in this study, as it was low for all the outcomes included. This is partly attributable to the methodological limitations already stated, but also to the imprecision of the studies, possibly due to the small sample sizes included in the primary studies [41].
Future studies can study the effect of different types of exercise on clinical rehabilitation goals among adults with DS. Studies with robust research designs and sample sizes consistent with the effect measure are required to evaluate the effects of exercise on the physical abilities of individuals with DS.
There is low certainty of the evidence for the outcomes proposed in this review. Therapeutic exercise, however, has proven to be effective in improving muscle strength and gait functionality. Standardized instruments that measure the outcomes in motor function and research of better methodological quality that assess the effectiveness of the exercise prescription parameters are required. This would facilitate the evaluation of the effectiveness of the intervention as well as decision-making in the practice regarding the type of exercise that would be indicated for each patient according to his or her therapeutic needs.
DS, Down syndrome; ADL, activities of daily living; RM, repetition maximum; RoB, risk-of-bias; MD, mean difference
Ethics approval and consent to participate
Not applicable
Consent for publication
Not applicable
Availability of data and materials
Not applicable
Competing interests
The authors declare that they have no competing interests
Funding
Not applicable
Authors’ contributions
MMM performed the research, screening, selection, and analysis of the studies and data, performed the meta-analyses and was a major contributor in writing the manuscript.
EIRG confirmed that the studies selected met the study selection criteria, she was an instructor to perform the meta-analyses and was a major contributor in writing the manuscript.
All authors read and approved the final manuscript
Acknowledgements
We/The authors thank Crimson Interactive Pvt. Ltd. (Enago) – https://www.enago.com/es/ for their assistance in manuscript translation and editing. We thank to Jimmy Alexander Valencia Castro, for the support in the screening of the studies.
Table 1.
|
STUDY |
STUDY DESIGN |
Participants |
INTERVENTION |
DOSING |
OUTCOME MEASUREMENT INSTRUMENT |
Results |
|
Aguiar et al (2008) |
Quasi-experimental |
IG: 21 men Age: 23.3 ± 2.1 |
Monitored aerobic exercise of adapted judo training for 16 weeks. |
Mode: Adapted Judo. Intensity: Lactate threshold. Frequency: 3 times/week. Duration: 50 min/session. |
Gross motor skills: |
The judo training program significantly (P < 0.05) improved the GMFM-88 index of young adults with DS. |
|
Boer (2020) |
Experimental |
26 adults. Age 32.7 ± 6 years (13 men, 13 women). |
IG: Aerobic exercise in aquatic environment. Freestyle swimming training, accompanied by lively music and strictly controlled by the main test instructor using a whistle. CG: No structured intervention. |
Mode: Freestyle swimming in a 12-m long and 1.4-m deep pool. Swim a certain length of the pool and rest while a partner completes another length in the same lane. As soon as the partner reaches the middle of the lane, the other participant is instructed to swim. Frequency: 3 times/week. Duration: 20 min the first 4 weeks, 26 min the last 4 weeks.
|
Static Balance: Dynamic Balance: - Walk on a balance beam. Functional fitness: - 6‐min walk distance (6MWD). - 8-ft up and go. Muscular strength: - Sit-to-stand test. -Curl‐up modified. -Isometric push‐up. |
Static Balance: No significant differences (P > 0.05) in IG static balance: 5.9 (3.3). CG: 5.5 (4.1). Significant differences (P < 0.05) between groups in IG dynamic balance: 5.3 (1.2). CG: 3.5 (2.6).
Functional fitness: No significant differences (P > 0.05) for the 6MWD IG test: 553.8 (106.9). CG: 503.1 (118.7). Significant differences between groups (P < 0.05) in the 8-ft up and go test: IG: 5.4 (1.0). CG: 6.0 (0.9).
Muscle strength: Significant differences between groups for the three tests P < 0.05: Sit-to-stand test: IG: 14.3 (1.6). CG: 13.6 (1.6). Modified curl up: IG: 33.3 (30.1). CG: 16.6 (22.1). Isometric push up: IG: 79.8 (41.9). CG: 47.3 (35.1) |
|
Boer y de Beer (2019) |
Quasi- experimental |
23 adults. Age 31.4 ± 7.4 years. IG: 13 participants (8 men, 5 women). CG: 10 participants (5 men, 5 women). |
IG: Aerobic exercise in aquatic environment. Aquatic training. Sessions controlled and monitored by test instructors and senior Human Movement Sciences students (approximately one test instructor per two participants). CG: No intervention additional to ADLs. |
Mode: Aquatic training with arm circle exercises, lateral twists, walk in place, run in place, water scoops, lateral leg raises, back flutter kick, stomach flutter kick, jumping jacks, knee twists, side shift, squat jumps, lunge jumps, and longer jog, 1.4-m-deep pool. Duration: 6 weeks, 35 min the first 3 weeks, 45 min the last 3 weeks. Consider a 3-min warm up and 2-min cool down. Frequency: 3 times/week |
Static Balance: Dynamic Balance: - Walk on a balance beam. Functional fitness: - 6‐min walk distance (6MWD). - 8-ft up and go. Muscular strength: - Sit-to-stand test. -Curl‐up modified. -Isometric push-up. |
Static Balance: No significant differences P > 0.05 in the static balance IG: 6.6 (3.5). CG: 5.1 (3.6), nor dynamic IG: 5.6 (0.8). CG: 4.6 (2.1).
Functional fitness: Significant differences between groups P < 0.05 for the 6MWD test: IG: 602.1(98.7). CG: 519. 9 (111.9). No significant differences P > 0.05 in the 8-ft up and go test: IG: .3 (0.9). CG: .5 (0.9).
Muscle strength: Significant differences between groups P < 0.05 for sit-to-stand test GI: 14.5 (2.2). CG: 13.0 (1.8) and modified curl up GI: 37.9 (30.1). CG: 20.0 (28.3). Nonsignificant differences P > 0.05 for isometric push-up IG: 82.2 (50.9). CG: 36.5 (32.5). |
|
Boer y Moss, (2016) |
Experimental |
42 adults. Age 33.8 ± 8.6. (25 men, 17 women). IG1: 13 participants. IG2: 13 participants. CG: 16 participants. |
IG1: Continuous aerobic training (CAT) on a bicycle or treadmill. IG2: Interval training (IT) with 10–30-s sprints on a bike or treadmill The two IGs performed the intervention under the supervision of a licensed sport scientist and exercise physiologist in a 2:6 (professional:participants) ratio. CG: No intervention. |
Duration: 12 weeks. 30-min sessions the first six weeks (5-min warm-up, 20-min central act, 5-min cool down), the last six weeks’ sessions were increased by 5 min for the central activity Intensity: Warm up and cool down at 4 km/h Frequency: 3 times/week IG2: IT - Mode: Interval aerobic training on a bicycle (50%) or treadmill (50%) - Intensity: 10–30-s max sprints with 90-s low cadence, low intensity gait, or bike. |
Grip strength: Lower Body Strength: - Sit-to-stand test. Agility and dynamic balance: - 8-ft up and go. Aerobic capacity and functional ability: - 6-min walking distance test (6MWD). |
Grip strength: CAT: 26.1 kg (7.9). IT: 29.9 kg (8.9). CG: 25.5 kg (9.1). No significant differences between groups P = 0.57
Lower Body Strength: CAT: 15.2 (1.8). IT: 15.5 (1.8). CG: 13.3 (2.3). Significant improvements between groups P = 0.01 and only in the CAT group compared to the control group (P <0.05).
Agility and balance: CAT: 4.8 s (0.9). IT: 4.9 s (1.1). CG: 6.2 s (1.3). Significant improvements between groups P = 0.03 and only in the CAT group compared to the control group (P <0.05).
Aerobic capacity and functional ability: CAT: 563.2 m (74.9). IT: 562.6 m (81.7). CG: 495.9 m (85.2). Significant improvements between groups P = 0.01 and only in the CAT group compared to the control group (P <0.05). |
|
Carmeli et al 2002 |
Experimental |
26 older adults aged 57–65 years. Mild mental retardation. IQ ranging 56–75 according to the Stanford Binet scale. IG: 16 participants (10 women, 6 men). CG: 10 participants (6 women, 4 men). |
IG: Aerobic exercise with treadmill walking. Participants walked only between 9:30 and 11:30 am indoors under controlled conditions (23°C, 40% humidity). CG: They were instructed not to change their daily activity level. |
Mode: Endless treadmill walk. Intensity: Low resistance with 0% incline. Intensity: Speed below the threshold for breathlessness but as fast as they could comfortably tolerate Frequency: 3 times/week. Duration: 25 consecutive weeks. They initially walked for 10–15 min. The duration was gradually increased up to 45 min according to tolerance.
|
Dynamic balance and gait speed: Data were collected for peak torque (ft/lb) (highest individual value of three peak efforts), peak torque percentage of body weight (ft/lb/kg), and average power (watts). |
Timed up and go: IG: 25.9 ± 3 s. CG: 29.1 ± 3 s. Significant improvements between groups P < 0.05. Muscle strength: Significant differences are found in all three tests (maximum torque, % maximum torque of body weight and average power) of hamstrings and quadriceps in both men and women P < 0.01 |
|
Cowley et al 2011 |
Quasi- experimental |
30 adults with mild intellectual disabilities. Age: 28 ± 8 years. IG: 9 men and 10 women. CG: 11 participants. 8 men and 3 women. |
IG: progressive resistance training. Each participant worked one on one with a professional who supervised all the training sessions. CG: Maintained normal daily activities. |
Mode: Leg extension, leg curl, leg press, shoulder press, chest press, bicep curl, and tricep curl exercises performed on exercise machines Intensity: 3 sets of 8–10 reps per exercise. The weight lifted by the subject was recorded during the training period and progressively increased to constantly overload the muscle. Frequency: 2 days per week. Duration: 10 weeks |
Isometric and isokinetic strength of knee extensors and flexors: Biodex System 3 dynamometer. - Maximum isometric peak torque: 3 series of 3 maximum contractions with knee extensors and flexors at a joint angle of 45°, 60°, and 75° with 3 min interval between series. - Maximum isokinetic peak torque: 3 series of 5 maximum contractions with knee extensors and flexors at 60°/s with 3 min interval between series. Functional tasks of daily life: - Time to get up from a chair at different heights (30, 38, or 43 cm) as quickly as possible to an upright position with trunk and legs straight, keeping arms crossed over the chest. - Gait speed: Walk 7.62 m. - Go up and down 10 steps as fast as possible without using the support handrail and alternating feet and then go down. |
Isometric flexor strength: Significant differences between groups P > 0.05 in the three degrees of movement (45°, 60°, and 75°).
Isometric strength extensors: Significant differences in the IG in the three degrees of movement P < 0.05
Flexors and extensors isokinetic strength Significant differences in the IG P < 0.05 Getting up from a chair at different heights: No significant differences P > 0.05 in any of the chair heights (30 cm, 38 cm, 43 cm) or in the 5 repetitions. 10-step ascent and descent: Significant differences in the IG P < 0.05 in both tests. IG Ascent: .83 SD 1.19. CG: 5.10 SD 1.19. GI descent: 4.38 SD 1.19. CG: 6.23 SD 2.80. Gait speed: IG: 1.72 SD 0.20. CG: 1.71 SD 0.24. No significant differences P > 0.05 |
|
Davis y Sinning (1987) |
Quasi- experimental |
IG1: 6 men with DS. Age: 20–38.2 years. IQ ranging 32–41 IG2: 6 men with mental disabilities without DS. Age 18.5–36.2 years. IQ ranging 33–57 CG: 6 undergraduate and postgraduate students. Age: 19–24.3 years. Above average IQ. |
IG1 AND IG2: Strength training under the supervision of graduates and graduates in physical education who were instructed in the procedures. Individual records of weight, series and repetitions were set. CG: They exercised individually and recorded their own progress. |
Mode: bench press, triceps curls, and biceps curls with free weight. Intensity: 6–8 repetitions. The amount of weight for each particular set was progressively increased as the subjects were able to exceed 8 repetitions. Duration: 8 weeks Frequency: 3 times a week
|
Elbow flexor strength: Electromyography: Electrodes are placed on the flexor muscle group at the elbow (biceps brachii). Integrated EMG and torque measurements of the elbow flexor muscle group were recorded simultaneously during maximal effort and step loading procedures. |
Only half of the subjects increased their maximum voluntary contraction as a result of the training, but there were no significant differences between groups P > 0.05 As expected, the post measurements of the group without disabilities experienced more improvement than the other two groups with disabilities, being statistically significant. P < 0.001 |
|
Mendonca et al (2011) |
Quasi- experimental |
IG1: 13 participants (10 men, 3 women) with DS. Age: 36.5 ± 5.5 years. IG2: 12 participants (9 men, 3 women) without disabilities. Age: 38.7 ± 8.3 years. |
Combined resistance and strength exercise training The exercise sessions were supervised by an exercise physiologist and an assistant |
ENDURANCE TRAINING Intensity: target heart rate compatible with 65% (first three weeks) at 85% of VO2peak. Monitored with fc/participant clock Duration: 30 min. 12 weeks. Frequency: 3 days/week. Intensity: 10% increase in 12-RM load when participants were able to complete 14 reps for 2 consecutive sessions with proper technique Frequency: 2 days/week. |
Muscle strength: 12-RM protocol on variable resistance machines. - Leg press. - Chest press. - Vertical traction. - Lower back. - Leg extension. Each participant was asked to perform 15 reps with relatively light resistance followed by 30 s of recovery. Resistance was then increased, and each participant performed a maximum of 5 sets of 12 repetitions until the 12-RM was reached. The recovery period between sets was exactly 2 min, and increments of 2.5–5 kg were used as each participant approached fatigue. The 12-RM was defined as the maximum load lifted through a full range of motion for a total of 12 repetitions. For most participants, the 12-RM was determined in 3–4 attempts. |
Leg Press: IG1: 110.2 ± 52.6. IG2: 171.3 ± 56.5 Chest Press: IG1: 35.3 ± 12.2. IG2: 51.3 ± 21.0 Vertical Traction: IG1: 39.2 ± 14.1. IG2: 59.4 ± 15.3 Lower Back: IG1: 35.6 ± 7.4. IG2: 51.9 ± 19.3 Leg Extension: IG1: 30.1 ± 10.3. IG2: 52.7 ± 17.6 Participants with Down syndrome showed lower muscle strength than participants without disabilities in all dynamic exercises, both before and after training. Training was highly efficient in obtaining generalized improvements for 12-RM in both groups (P < 0.05). The magnitude of these improvements was similar between participants with and without Down syndrome. |
|
Rimmer et al (2004) |
Experimental |
52 adults with DS. Mean age 39.4 ± 6.4 IG: 30 participants. CG: 22 participants. without intervention. |
IG: Cardio and strength exercises. Exercise classes were supervised by a full-time registered clinical exercise physiologist and two assistants |
CARDIOVASCULAR TRAINING Duration: 15–20 min the first 2 weeks, 20–30 min the third and fourth weeks, 30 min from the fifth week onward for 12 weeks. Intensity: 50%–70% of VO2 max. Monitored with cardiac monitors. STRENGTH TRAINING Mode: seated bench and leg press, seated leg curl, triceps curl, seated shoulder press, seated row, push-up. |
Strength: 1-RM protocol according to the ACSM. Leg press Chest press Grip Strength: Manual dynamometry |
Leg Press: IG: 320 lb (87) 145.1 kg (39.4). CG: 208 lb (97) 94.3 kg (43.9). Significant differences P<0.0001 Chest Press: IG: 100.7 lb (44.9) 45.6 kg (20.3). CG: 59.9 lb (33.6) 27.1 kg (15.2). Significant differences P<0.0001 Dynamometry: IG: Right hand 22.0 (8.1); Left hand 21.6 (8.7) CG: Right hand 19.0 (7.7); Left hand 17.8 (7.0) Nonsignificant differences neither on the left nor on the right side P > 0.05 |
|
Shields et al (2008) |
Experimental |
20 adults. Age: 26.8 ± 7.8 years. 13 men, 7 women. IG: 9 participants. CG: 11 participants.
8 of the 20 participants worked at least 1 day/week in manual-type jobs (packing confectionery boxes, sorting and cutting clothes, and assembling car parts).
|
IG: Group progressive resistance training in a supervised community gym. The trainer kept a record for each participant of the number of repetitions and sets and the weight lifted/exercised in each session. Participants completed the program in a group, supervised by 2 accredited fitness trainers. Each trainer supervised the training of a subgroup of 2–3 participants. CG: Continued with usual activities (work, free time, and leisure). |
Mode: Progressive resistance training with machines: - Shoulder press. - Seated chest press. - Seated rowing. - Seated leg press. - Knee extension. - Seated calf raise. Intensity: Increased when 2 sets of 12 reps per exercise could be completed. Volume: 2–3 sets of 10–12 reps per exercise to failure. Frequency: 2 times a week. Duration: 10 weeks Density: 2-min rest between sets |
Muscle performance: - Muscular resistance: repetitions of chest and leg press with 50% of 1RM. Physical function: - Timed up and down stairs test. - Grocery shelving task: Get up from a chair and take 2 bags of groceries to a bench located 2 m away. Each bag contains 10 items (410 g each, total weight of each bag 4.1 kg). Then they have to take the items out of the bag and stack them on a shelf at shoulder height. |
1 RM Chest Press: IG: 44.9 ± 15.2 kg. CG: 31.6 ± 13.3 kg. 1 RM Leg Press: IG: 96.2 ± 31.6 kg. CG: 82.2 ± 19.7 kg. Rep Chest Press: IG: 25.9 ± 8.3. CG 17.5 ± 9.5. Rep Leg Press: IG: 46.8 ± 37.1. CG: 49.4 ± 27.6. Timed up and down stairs: IG: 14.4 ± 3.4 s. CG: 18.7 ± 6.5 s. Grocery shelving task: IG: 67.5 ± 33.4 s. CG: pre 122.8 ± 84.0 s; post 110.7 ± 66.4 s. Significant differences between groups in 1-RM chest press (P 0.08), chest press repetitions (P 0.002), and leg press repetitions (P 0.039). No significant differences between groups in the leg press 1RM test (P 0.90), timed up and go (P 0.12) or grocery shelving task test (P 0.11) |
|
Silva et al (2017) |
Experimental |
27 adults aged 18–60 years IG: 14 participants. CG: 13 participants. |
IG: Wii-based exercise program that included training games for aerobic endurance, balance, and isometric strength. CG: They completed their usual daily activities (usual treatment) at their occupational center, such as rehabilitation, life skills training, and art-related activities. |
Mode: Aerobic exercise through a Wii-based exercise program. Individual sessions or with another participant (half of the sessions in each format). Frequency: 3 sessions per week. Duration: 2 months. |
Physical aptitude: Eurofit test battery: - Limb movement speed (Plate Tapping Test) - Static arm strength (Handgrip Test) - Running speed and agility (Shuttle Run) - Balance (Flamingo Balance) - Flexibility (Sit and Reach) - Explosive power of the legs (Standing Broad) - Trunk Strength (30-s Sit-ups) - Muscular resistance (Bent Arm Hang) Functional mobility: - Timed Up and Go. - Response speed subtest of the Bruininks–Oseretsky Motor Competence Test First Edition. Motor skills:
|
Significant improvements in the GI in the Handgrip test (IG: 25.42 (5.53). CG: 23.92 (6.45) P 0,025), in the sit and reach (IG: 36.92 (7.22). CG: 29.46 (10.53) P 0,014), in the standing broad (IG: 99.33 (29.49). CG: 90.69 (35.20) P <0,001) and in the Bruininks–Oseretsky First Edition test (IG: 4.67 (2.81). CG: 4.77 (2.17) P 0.028) Significant differences between groups were identified in the plate tapping test (P 0.045), shuttle run (P 0.014), sit and reach (P 0.027), standing broad (P 0.003), 30-s sit-ups (P 0.040) and timed up and go (P 0.049) No significant differences in the handgrip test (P 0.837), flamingo balance (P 0.477), bent arm hang (P 0.086), Bruininks–Oseretsky First Edition (P 0.265), neither in the beanbag overhead nor in the hand right P 0.150 nor in the left P 0.083 |
|
Skiba et al (2019) |
Experimental |
22 adults aged 25– 40 years, with moderate intellectual disability (IQ: 36–51). 11 men, 11 women. IG: 11 participants. CG: 11 participants. |
IG: Aerobic exercise with Nordic walking training program. The exercises were performed by a physiotherapist, who was a qualified Nordic walking instructor. CG: Did not undergo any training. |
Mode: Brisk Nordic walking. Intensity: Progressed over the course of the training sessions. Frequency: 3 times a week. |
Spatiotemporal parameters (step and stride length and speed) and maximum values of angles in the ankle, knee, hip, and shoulder joints in different phases of gait: |
Gait parameters: Significant differences in the right (P 0.002) and left (P 0.038) step length as well as for the right (P 0.002) and left (P 0.001) stride length. Regarding speed, only significant changes in right leg (P 0.011). Angular values: Significant changes for the right ankle (P 0.044) in support phase. Significant changes in the left knee, with increased flexion in the phase of medium support (P 0.002), terminal support (P 0.017) and initial sway (P 0.004). The hip does not present significant changes in the right or left leg during the initial contact (P 0.649–0.755), pre-swing (P 0.054–0.165) or terminal sway (P 0.738–0.896). Significant differences in the movement of the pelvis in the sagittal plane in the medium support phase for the right limb (P 0.038) and in the initial sway phase for the left limb (P 0.043). In the frontal plane, there were significant differences in the movement of the pelvis at the maximum point of movement of the left limb (P 0.027) and at the minimum point of movement of the right (P 0.002). In the transverse plane there are no significant differences in the right or left leg. |
IG: Intervention group. CG: Control group. DS: Down Syndrome. ADL’S: Activities of daily living
Table 2. Assessment of the certainty of evidence presented for each outcome
|
Evaluation of certainty |
Summary of outcomes |
Relevance |
||||||||||
|
No. of studies |
Study design |
Risk of bias |
Inconsistency |
Indirect evidence |
Imprecision |
Other considerations |
No. of patients |
Effect |
Certainty |
|||
|
Therapeutic exercise |
Control |
Relative |
Absolute |
|||||||||
|
Muscular strength – Modified Curl Up (monitoring range 6–8 weeks; assessed with Repetitions of sit-ups) |
||||||||||||
|
2 |
Randomized trials |
Seriousa |
not serious |
not serious |
serious b |
none |
26 |
23 |
- |
MD 10.73 higher |
⨁⨁◯◯ |
CRITICAL |
|
Muscular strength – Isometric push up (monitoring range 6–8 weeks; assessed with Time held in push-up position) |
||||||||||||
|
2 |
Randomized trials |
Seriousa |
not serious |
not serious |
serious b |
none |
26 |
23 |
- |
MD 24 higher |
⨁⨁◯◯ |
CRITICAL |
|
Muscular strength – Sit-to-stand test (monitoring range 6–12 weeks; assessed with Number of repetitions) |
||||||||||||
|
3 |
Randomized trials |
Seriousa |
not serious |
not serious |
serious b |
none |
39 |
39 |
- |
MD 0.39 higher |
⨁⨁◯◯ |
CRITICAL |
|
Muscular strength - 1 RM Leg Press (monitoring range 10–12 weeks; assessed with Weight Lifted) |
||||||||||||
|
2 |
Randomized trials |
Seriousc |
not serious |
not serious |
serious b |
none |
39 |
33 |
- |
MD 18.47 higher |
⨁⨁◯◯ |
CRITICAL |
|
Muscular strength - 1 RM chest press (monitoring range 10–12 weeks; assessed with Weight lifted) |
||||||||||||
|
2 |
Randomized trials |
Seriousc |
not serious |
not serious |
serious b |
none |
39 |
33 |
- |
MD 11.93 higher |
⨁⨁◯◯ |
CRITICAL |
|
Balance - Static (monitoring range 6–8 weeks; assessed with Time maintaining monopodal support) |
||||||||||||
|
2 |
Randomized trials |
Seriousa |
not serious |
not serious |
serious b |
none |
26 |
23 |
- |
MD 0.43 higher |
⨁⨁◯◯ |
IMPORTANT |
|
Balance - Dynamic (monitoring range 6–8 weeks; assessed with Consecutive steps on balance beam) |
||||||||||||
|
2 |
Randomized trials |
Seriousa |
not serious |
not serious |
serious b |
none |
26 |
23 |
- |
MD 0.55 higher |
⨁⨁◯◯ |
IMPORTANT |
|
Functional Fitness – 6 minute walking distance (6MWD) (monitoring range 6–12 weeks; assessed with 6MWD) |
||||||||||||
|
3 |
Randomized trials |
Seriousa |
not serious |
not serious |
serious a |
none |
39 |
39 |
- |
MD 43.21 higher |
⨁⨁◯◯ |
IMPORTANT |
|
Functional Fitness – 8-ft up and go (follow-up range 6–12 weeks; assessed with Time to walk 2.4 m round trip and return to sitting position) |
||||||||||||
|
3 |
Randomized trials |
Seriousa |
not serious |
not serious |
serious b |
none |
39 |
39 |
- |
MD 0.34 lower |
⨁⨁◯◯ |
IMPORTANT |
a High risk of bias in random sequence generation and unclear in masking
b Wide confidence intervals that pass the line of no effect
c Unclear risk of bias in 4 of 7 criteria