3.1 Study Selection
Database searching returned 425 potential systematic reviews. The numbers of systematic reviews screened, assessed for eligibility, and included in the review after taking into account The PRISMA extension statement for reporting of systematic reviews [37], are shown in Fig. 1. A total of 12 systematic reviews involving 117 studies included publications from 2007 to 2020. Inter-rater kappa scores of agreement were high for both screening of abstracts (k = 0.947, SE = 0.52) and full-text articles (k = 0.957, SE = 0.42). The percent agreement for admissibility of systematic reviews during full-text critical appraisal was 91% (10/11). The consensus during the inclusion of reviews was reached through discussion between the two primary reviewers (SR and FA) and did not require further deliberation from a third, independent reviewer. Fig. 1 Search strategy results.
3.2 Study Characteristics
Six systematic reviews examined muscular fitness (strength and endurance), six systematic reviews examined dynamic and/or static balance [16, 18, 21, 23, 24, 25, 26, 27], four systematic reviews examined cardiovascular fitness[16, 24, 25, 26], and three systematic reviews examined anthropometric measurements [16, 22, 26], and three systematic reviews examined locomotor and functional performance [17, 18, 20]. Tables 4 and 5 show the outcomes of each review, as well as the number of papers included, the meta-analysis summary, and the adjusted R-AMSTAR ratings. The following were the reasons for the exclusion of nine carefully examined reviews. three studies focused solely on children with cerebral palsy, two were not systematic reviews, two did not look at motor functions affecting performance, and two did not have full-text versions accessible.
Table 4
R-AMSTAR scores: total and rank [18]
Systematic review | Modified R- AMSTAR items |
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | total | % | Rank |
Li et al, 2013 | 3 | 4 | 4 | 2 | 3 | 4 | 4 | 0 | 4 | 1 | 3 | 32 | 80% | B |
Khondowe et al, 2007 | 3 | 4 | 4 | 3 | 2 | 4 | 2 | 1 | 4 | 1 | 2 | 30 | 75% | C |
Sugimoto et al, 2016 | 3 | 1 | 3 | 2 | 1 | 4 | 4 | 1 | 4 | 1 | 3 | 27 | 67.5% | D |
Damiano and Dejong 2009 | 3 | 4 | 4 | 4 | 3 | 4 | 4 | 0 | 1 | 2 | 2 | 31 | 77.5% | C |
Gudiol et al, 2017 | 4 | 4 | 4 | 4 | 3 | 4 | 4 | 0 | 4 | 3 | 2 | 36 | 90% | A |
Koopman, 2020 | 4 | 1 | 3 | 1 | 1 | 4 | 3 | 0 | 1 | 1 | 1 | 20 | 50% | E |
Espinosa et al., 2020 | 4 | 2 | 3 | 4 | 3 | 4 | 4 | 0 | 3 | 1 | 2 | 30 | 75% | C |
Zago et al., 2020 | 3 | 4 | 3 | 2 | 3 | 4 | 4 | 0 | 1 | 1 | 2 | 25 | 62.5% | D |
Hardee and Fetters, 2017 | 4 | 4 | 4 | 3 | 3 | 4 | 4 | 1 | 1 | 1 | 3 | 32 | 80% | B |
Gonzalez et al., 2019 | 4 | 4 | 4 | 4 | 3 | 4 | 3 | 1 | 4 | 3 | 3 | 37 | 92.5% | A |
Paul et al.,2019 | 3 | 3 | 4 | 1 | 4 | 3 | 3 | 1 | 2 | 1 | 4 | 29 | 72.5% | C |
Maiano et al., 2019 | 4 | 3 | 4 | 3 | 4 | 4 | 3 | 1 | 1 | 1 | 3 | 31 | 77.5% | C |
Average | 3.5 | 3.2 | 3.6 | 2.7 | 2.7 | 3.9 | 3.5 | 0.5 | 2.5 | 1.4 | 2.5 | 30 | 75% | C |
Table 5
Characteristics of included systematic review
Systematic review | Aim | ICF level | Range of age (years) | Modified R-AMSTAR Total / Rank | No. of studies/No. of children | Outcome variable | Standardized measures | Interventions | Meta-analysis summary |
1. Lie et al.,2013[16] | To assess the benefits of physical fitness in D.S children | Body structure and function | 3–18 | 32 / B | 10/349 | Muscular fitness(strength &endurance) -balance, cardiovascular fitness (the peak vo2) and -body composition | -Isokinetic strength -Standing balance test -Treadmill test and rowing ergometer test -BMI and body fat | a treadmill program, a bicycle program, a rowing ergometer intervention, a progressive resistance training game-like balance exercise, cardiovascular and strength exercise, and a weight-bearing exercise program | No meta-analysis performed. |
2. Khondowe et al, 2007 [17] | To evaluate the effect of physical activity on motor development in children with D.S | Activity & participation | > 10 | 30/ C | 4/ 146 | Independent walking Locomotor skills (developmental quotient) | -Bayley scale of infant development -10 step forward walking and 10 step side walking | sensory integrative therapy ; vestibular stimulation, Neurodevelopmental therapy | Meta-analysis performed on 2 studies showed a significant effect for both measures. |
3. Sugimoto et al,2016 [18] | To examine the effects of neuromuscular training on general strength, maximal strength, and functional mobility tasks in children with D.S | Body structure and function & activity | > 20 | 27/ D | 7 /309 | -general strength studies) -Maximal strength-Functional mobility performance | -isometric, isokinetic strength -One repetition maximum(1 RM) of leg and chest press -grocery shelving and timed up- and- downstairs | weight machine exercises(resistance training), a 5-min treadmill exercise and a 20-min virtual-reality based activity, a whole-body vibration training | Meta-analysis performed on 5 studies showed a significant effect for general and maximum strength & non-significant for functional performance. |
4. Damiano and Dejong, 2009 [19] | to investigate the evidence supporting treadmill training with and without body weight support across broader diagnostic categories within pediatric neurorehabilitation. | Body structure and function | 13–15 | 31/ C | 6 out 29/ 186 | -Trunk & leg activity duration -cadence, velocity, step length, width, dynamic base, double support percentage, foot rotation & symmetry - the onset of independent walking | -Acti watch activity monitors for 24 hrs -Milestone achievement scale | treadmill training | Meta-analysis not performed |
5. Gudiol et al., 2017 [20] | To assess the effectiveness of treadmill interventions on locomotor development in children with delayed ambulation or in pre-ambulatory children | Activity & participation | > 6 | 36/ A | 7/ 175 | The onset of independent walking and locomotor skills | -GMFM, BSITD; PDMS – 2 -motion analysis systems | treadmill training | Meta-analysis on 2 studies showed no significant effect on independent walking and significant on locomotor skills. |
6.Koopman, 2020 [21] | To identify which interventions have been used between 2010 and 2020 for improving balance in individuals with Down Syndrome | Body structure and function | +_ 18 | 20/ E | 6/ 147 | Static & dynamic balance and LL strength | BOTMP, KTK, PBS & Handheld dynamometer for lower extremity strength testing | BOSU Ball training exercises, Six-week strength and balance training program, Dance based training program, Whole body vibration training, Virtual reality therapy, Wiihabilitation | Meta-analysis not performed |
7. Espinosa et al., 2020 [22] | to analyze the relationship between dietary intervention, physical exercise, and body composition, in DS with overweight and obesity | Body structure and function | > 19 | 30/ C | 6/ 163 | anthropometric measures (BMI & body fat) | Bod Pod® plethysmography equipment& a Holtain lipometer | a physical exercise program with different aerobic and resistance activities | Meta-analysis not performed |
8. Zago et al., 2020 [23] | To describe (1) the current knowledge on gait and postural control in individuals with DS, and (2) relevant rehabilitation strategies | Body structure and function & activity | > 18 | 25/D | 9 out of 37/ 324 out of 1299 | Postural control & spatiotemporal parameters | an unstable foam rubber mat over a pressure plate | treadmill training | Meta-analysis not performed |
9. Hardee and Fetters, 2017 [24] | To evaluate the effectiveness of exercise intervention on daily life activities and social participation in individuals with DS | Body structure and function & activity & participation | > 18 | 32/ B | 11 out of 19/ 289 out of 525 | Balance Cardiovascular , muscle strength and endurance | -BOTMP - maximal oxygen consumption VO2, heart rate (HR),respiratory rate (RR), height/weight/skinfolds handheld manual muscle tester& 10 repetition maximum (RM)1 RM seated chest press), (1 RM seated leg press) | progressive resistance training, aerobic and strength training, bike riding, dance | Meta-analysis not performed |
10. Gonzalez et al., 2019 [25] | To evaluate the effectiveness of PT on the physical outcomes (such as vestibular, cardiovascular and respiratory, weight maintenance and movement-related functions, motor skills, carrying out tasks, mobility and walking indexes) in people with DS. | Body structure and function & activity & participation | > 18 | 37/ A | 21out of 27/ 689 out of 842 | muscle strength balance Cardiovascular function Motor development - | - Dynamometer,-1RM repetition maximum tests. -Bruininks Oseretsky Test of Motor Proficiency, Balance platform, Biodex balance system. -Treadmill exercise test with gas consumption control and electrocardiogram. -Gross Motor Function Measure, Bayley Scales of Infant Development, Peabody Developmental Motor Scales. | treadmill training, Progressive resistance training, Full-body vibration, Neurodevelopment therapy and massage therapy, Supramalleolar orthosis | Meta-analysis of 4 studies on muscle strength & 2 studies on balance showed a significant effect. In Cardiovascular function, the meta-analysis of 2studies shows inconclusive results. |
11. Paul et al.,2019 [26] | To discusses the benefits of exercise therapy on body composition, aerobic capacity, muscle strength, proprioception and cardiometabolic profiles of PWDS. | Body structure and function | a mean age of 18.1 ± 6.8 years | 29/C | 19/1331 | Anthropometric measurements, muscle strength and endurance of DS | -BMI, WC, BW -Bruininks Oseretsky Test of Motor Proficiency, - accelerometer, a 6 -min walk test | Regular aerobic exercises, Regular muscle strengthening exercises | Meta-analysis not performed |
12. Maiano et al., 2019 [27] | To summarize the findings from studies examining the effects of exercise interventions designed to improve balance in youths with Down syndrome | Body structure and function | 5–22 | 31/C | 11/281 | Static balance Dynamic balance | -BOTMP (balance subtest), Pressure platform. -Biodex Balance System, Heel-to-Toe Dynamic Balance Test. | Strength and balance exercises, Whole body vibration, and Wii Fit balance game training | Meta-analysis not performed |
3.3 Outcome Measures
Diverse outcome measures were used corresponding to the different kinds of intervention programs. The majority of the studies assessed muscular fitness and balance, four studies evaluated cardiovascular fitness; three studies for body composition, and three studies tested locomotor skills which terms classified according to ICF (detailed information is presented in Table 5).
3.3.1 Study Outcomes – Muscle Strength And Endurance
Six systematic reviews looked into the effects of an intervention program on muscle strength and endurance, with different training methods used in each study.
In the study conducted by Li et al. (2013), a treadmill program, a bicycle program, a rowing ergometer intervention, and progressive resistance training were employed; the meta-analytic data demonstrated that exercise programs can improve muscular strength. The conflicting results among research may be due to the effects of different exercise types [16].
In Sugimoto et al. (2016); weight machine exercises(resistance training), A 5-minute treadmill activity were employed as weight machine exercises (resistance training). Their findings suggested that neuromuscular training could be an effective strategy for improving overall and maximal muscle strength in Down syndrome children and young adults [18].
In Hardee and Fetters, (2017); A favorable impact of an exercise intervention on daily living activities and involvement for people with DS was demonstrated using progressive resistance training [24].
Treadmill training with progressive resistance training was employed by Gonzalez et al ( 2019); the meta-analytic data on strength levels emphasize the importance of resistance training programs in improving muscle strength in patients with DS [25].
Regular muscular strengthening exercises, such as circuit training, plyometric, and swimming, as well as regular resistance training, were used by Paul et al (2019). Regular exercise improves the health condition of PWDS by improving their body composition, aerobic capacity, and muscle strength, according to clinical research [26].
In Koopman et al., (2020), a Six Week Strength and Balance Training Program was used to examine lower limb strength. Resistance exercises with sandbags for hip and knee flexors, hip and knee extensors, hip abductors, and ankle plantar flexors made up the strength training element of the intervention program. Subjects did two sets of ten repetitions at 50% of their one-repetition maximum (1RM), and resistance was increased only after the participants could complete the sets with ease; the results showed that after a six-week exercise program, the participants' one repetition maximum (1RM) had decreased by 10%. The intervention group was stronger than the control group in all muscle groups whose strength was measured. These results were statistically significant (p < 0.05) [21].
3.3.2 Study Outcomes – Balance
Six systematic evaluations looked at how different exercise regimens affected the result of balance interventions. A treadmill program, particular balance exercise training, and a weight-bearing exercise program were used by Lie et al (2013). Exercise innovations increased balance, according to meta-analytic data [d = 1.10; 95 percent CI (0.55, 1.63); Q2 = 1.10; P = 0.58; I 2 = 0; fail-safe n = 14 [16].
Aerobic and strength training, bike riding, and dance were used by Hardee and Fetters(2017). Studies with statistically significant body structure and function measures were shown to have lesser validity than studies with Activity and Participation measures [24].
Gonzalez et al. (2019) employed full-body vibration. The intervention had a beneficial effect on mediolateral oscillations of the center of gravity controlling body posture, according to the meta-analysis [25].
Strength and balance workouts, whole-body vibration, and Wii Fit balance game training were used by Maiano et al, (2019). The findings revealed that the exercise programs studied are more effective than control conditions in improving static and static-dynamic balance in children with Down syndrome [27].
BOSU Ball training activities, a Dance-based training program, Whole body vibration training, Virtual reality therapy, and Wii rehabilitation were employed by Koopman et al (2020). Children with Down Syndrome achieved much-improved balance in both static and dynamic balance tasks when using the BOSU ball. Although the results of the dance program did not show any significant variations in the static balance of people with Down syndrome, the findings suggest that sensory integration training could help these people with their balance and coordination [21].
The results of the whole-body vibration training study reveal that it is only useful in people who have a problem with their balance. The virtual reality program's results imply that virtual reality therapy is an effective tool for improving balance and motor coordination in people with Down syndrome and that it might be suggested as a clinical treatment for this population. The results of the Wii-Fit Virtual Reality, or Wii-habilitation, study demonstrate that VR-based therapy in the form of Wii-habilitation, when used in conjunction with regular physical therapy, can help people with Down syndrome improve their balance [21].
Treadmill training was employed by Zago et al (2020). After a 6-month treadmill training program, improvements in dynamic balance function were reported in the elderly with DS [23].
3.3.3 Study Outcomes – Cardiovascular Fitness
As a result of four systematic reviews, cardiovascular fitness was assessed and the peak VO2 was measured. A treadmill test and a rowing ergometer test were employed by Lie et al., (2013). Through rowing ergometer training, there was no group difference in peak VO2, as determined by a treadmill test [d = 0.37; 95 percent CI (– 0.62, 1.36)] and a rowing ergometer test [d = 0.30; 95 percent CI (– 0.68, 1.29). Exercise therapies enhanced cardiovascular fitness [d = 0.60; 95 percent CI (0.07, 1.14); Q1 = 1.74; P = 0.19; I 2 = 42.41; fail-safe n = not applicable], according to the meta-analysis [d = 0.60; 95 percent CI (0.07, 1.14); Q1 = 1.74; P = 0.19; I 2 = 42.41; fail-safe n = not applicable [16].
Aerobic and weight training, bike riding, and dance were used to quantify peak aerobic capacity (maximal oxygen consumption, heart rate) in Hardee and Fetters(2017) [24].
The results of the meta-analysis revealed that the data presented by the studies were equivocal, according to Gonzalez et al.,(2019). VO2 max examined the maximal heart rate with an intervention based on aerobic exercise [25].
The study by Paul et al.,(2019) showed that regular aerobic exercise boosted the aerobic capacity of PWDS, which was the main contributor to maximal oxygen consumption, and thus needs further validation through more randomized controlled trials [26].
3.3.4 Study Outcomes – Body Composition
The effects of physical fitness training on body composition were studied in three systematic reviews. In Lie et al.,2013; cardiovascular, bicycle, and strength exercise training had no statistically significant impact on body weight [d = 0.05; 95 percent CI (– 0.50, 0.60)], BMI [d = 0.04; 95 percent CI (– 0.51, 0.59)], or skinfold score [d = – 0.37; 95 percent CI (– 0.93, 0.18)], but the combined exercise training programme (i.e. jumps, press ups, elastic bands) had statistical significant difference [16].
Espinosa et al., 2020; used a physical training program with diverse aerobic and resistance activities to measure anthropometric measures (BMI and body fat) utilizing Bod Pod® plethysmography equipment and a Holtain lipometer. The procedures that caused the largest variation in body composition in children and adolescents were those based on planned physical activity, considering intensity, duration, number of repetitions, days per week, and programming by macrocycles, according to this review [22].
Paul et al.,2019; Clinical research suggests that regular exercise improves the health status of PWDS by improving their body composition, aerobic capacity, muscle strength, proprioception, and postural stability. The benefits of improved aerobic work capacity and body composition contribute to a decreased cardiometabolic risk profile in people with Parkinson's disease [26].
3.3.5 Study Outcomes – Locomotor Skills
The impact of physical therapy training techniques on locomotor skills was studied in three systematic reviews.
Independent walking and locomotor skills (developmental quotient) were measured using the Bayley scale of baby development and 10-step forward and 10-step side walking (Khondowe et al, 2007). The therapies used were sensory integrated treatment, vestibular stimulation, and neurodevelopmental therapy. The time it takes for Down Syndrome youngsters to walk independently is greatly reduced when they get intensive physical care. Furthermore, intense physical therapy considerably improves the total and locomotor development quotients [17].
The effect of neuromuscular training on functional mobility tasks was investigated by Sugimoto et al. in 2016. (grocery shelving and timed up-and-down stairs). The intervention had a tiny, statistically non-significant effect on grocery shelving and timed up-and-down stairs, according to the meta-analysis results (SE: 0.11, 95 percent CIs: 0.47, 0.69, p = 0.71) [18].
Gudiol et al., 2017; GMFM, BSITD, PDMS – 2, and motion analysis systems were used to examine the start of independent walking and locomotor skills using treadmill intervention. The meta-analysis found no difference between the two intervention groups in the age of onset of independent walking (MD 0.10, 95 percent CI-5.96 to 6.16). Other gait measures such as step width (MD -0.58, 95 percent CI -2.11 to 0.95) and step length (MD2.68, 95 percent CI-0.99 to 6.35) did not differ between the high-intensity and low-intensity treadmill intervention groups at the 12-month follow-up assessment. Gait ankle dorsiflexion (MD -2.80, 95 percent CI -5.96 to 0.36); and toe-off (MD -0.90, 95 percent CI-5.49 to 3.69) [20].
3.3.6 Meta-analysis Of Individual Primary Studies
R-AMSTAR rank did not differ between meta-analyses reporting significant and non-significant findings. Thus, the methodological quality of each systematic review was not a strong predictor of overall effect or significance. A meta-analysis of included primary studies from systematic reviews of the same methodological quality was performed, if outcomes were comparable. Findings not suitable for meta-analyses were summarized qualitatively [13, 14]. Meta-analyses were conducted in Rev-Manager version 5.0 (Copenhagen, Denmark: the Nordic Cochrane Centre, the Cochrane Collaboration, 2008). Standard mean difference (SMD) and 95% confidence intervals (CIs) were calculated. A summary of total effect sizes for four primary included studies, in addition to respective 95% CIs and PIs, is provided for locomotor developmental skills outcome in Fig. 2.