Title: Acute effects of self-myofascial release compared to dry needling on myofascial pain syndrome related outcomes: range of motion, muscle soreness and performance. A randomized controlled trial.


 Objectives: myofascial pain syndrome (MPS) is associated with reductions in range of movement (ROM), decrease in physical function and performance and increase in pain in different populations. Elucidating the best prevention and treatment strategies for MPS has been one of the main goals in the last decade. The objective of the present study was to compare the acute effects of self-myofascial foam rolling (SFR) and dry-needling (DN) techniques on ankle dorsiflexion ROM, soreness post-needling and performance through countermovement jump (CMJ) height. Methods: a prospective crossover design composed by 12 active adults, aged 23.41 ± 1.68 years (weight: 78.33 ± 9.02 Kg; height: 1.79 ± 0.088 m) with active ankle dorsiflexion restriction was performed. Participants were randomized into the SFR and DN techniques to analyze its effects on ankle dorsiflexion ROM, muscle soreness and jump height at pre, post and 24 h post-intervention. Results: significant improvements were found by DN on ankle dorsiflexion at 24 hours post intervention and muscle soreness by SFR at the same time point. No significant differences were found between conditions. Conclusions: Both SFR and DN are effective in improving ankle dorsiflexion and performance in young adults without producing an acute effect in muscle soreness.


INTRODUCTION
Injury prevention and recovery strategies are two basic areas in sport and physical exercise fields. One of the aspect that have generated most interest in the last decade in these two areas has been the myofascial pain syndrome (MPS) 1 . MPS usually appears when the demands in sport and exercise activities exceeds the tolerance capacity of the muscle tissue, leading with pain, weakness and lack of mobility 2 . The appearance of myofascial trigger points (MTrPs) has been described within the MPS as something common 3 .These are defined as a hypersensitive area in a tight band of a muscle 4 .
In recent years, foam rolling has become one of the main tools used for the treatment of MPS as well as for the recovery of muscle tissue after the damage produced by the sport and exercise activities 5 . Foam rolling has shown beneficial effects on improving hamstring range of movement (ROM), muscle stiffness, late onset of pain and also pressure pain threshold (PPT) 6 .
On the other hand, another treatment used in MPS is the dry needling (DN) technique 7 .
This tool has been shown to be effective to relieve pain and increase ROM in the shortterm 8 . For example, a meta-analysis performed by Gattie, Cleland and Snodgrass 9 revealed that very low quality to moderate quality evidence suggests that DN is more effective that no treatment for reducing pain and improving PPT.
Interestingly, a recent meta-analysis leaded by Wiewelhove et al. 10 showed that a treatment with SFR shows minors and partially negligible positive effects on performance and muscle recovery. However, the use of foam roller could be beneficial in some cases as it increases sprint performance and flexibility. In addition, previous studies have detected that self-myofascial foam roller (SFR) can also reduce muscle pain sensation 11 .
However, regarding the DN technique, one of the main side-effects is the appearance of post-needling soreness. This post-needling soreness response is variable, and despite the fact that not all subjects experience it with the same intensity level, the risk of the its appearance could determine the choice of this technique over others 12 . However, this symptom does not have to affect the muscle contractile properties 13 . Therefore, the present study aimed to examine and compare the acute effects in terms of magnitude and duration of SFR and DN techniques on ankle mobility, pain and jump height in active and healthy young adults. We hypothesized that both interventions, SFR and DN, would lead similar acute (immediate and post 24h) effects on all the parameters analyzed, with no significant differences between conditions in any of them. Table 1 shows the descriptive statistics of all dependent variables analyzed during both intervention conditions. The 12 participants who where initially randomly assigned to each condition received the treatment and were analyzed for the primary and secondary variables. There were no dropouts.    The RM ANOVA did not show significant differences in main effect of "intervention"

ADVERSE EVENTS
No adverse events or unintended effects were recorded. Contrary to some studies, which showed negative effects on performance when SFR was applied in pre-competition 18 , we found that the gains in ankle flexibility did not have a negative impact on performance, evaluated through the jump height in a CMJ. However, our results are in line with previous research where knee, ankle, hip and trunk ROM improvements also had no negative consequences on different performance parameters 19 . It should be noted that the effects reported in our studies were acute effects. These discrepancies between studies can be related with the heterogeneity in the protocols of SFR applied and in the samples.

DISCUSSION
Several possibilities such us the activation mechanoreceptors and autonomic nervous system response 20 could be considered responsible for the changes of the ankle ROM due to the activation of central pain modulatory paths, through neural inhibition mechanisms 21 . In fact, the application to the lower extremity prior to the activity does not enhance or negatively affect muscle performance but may change the perception of fatigue 22 . In fact, there is an emerging consensus on how SFR treatment affects improving power, strength, elasticity and balance in athletes. However, no significant anatomical changes has been observed in fascicle length in the gastrocnemius muscle 15 .
On the other hand, among the existing tools for the treatment of MPS, together with noninvasive myofascial self-liberation techniques such as the aforementioned SFR, there are techniques with an invasive approach such as wet needling or DN. DN has been recommended for management MTrPs pain 23 . MTrPs dry needling procedures have shown to be associated with post-needling soreness which usually lasting less than 72 hours 24 . This post needling soreness will not be of similar intensity in all patients, and some of them may not even perceive said post-intervention sequelae.
Although the symptom is not reported by all patients equally, there are previous studies that show that in asymptomatic patients, the use of DN over latent MTrPs within the medial gastrocnemius muscle produced an increase in magnetic resonance imaging using the Short Tau Inversion Recovery sequence (MRI-STIR), compatible with intramuscular edema and an increase of muscle stiffness 13 . Due to this important sideeffect, it is very necessary for physical therapists to know the clinical conditions and time periods for which DN produced post-needling soreness. It is well-known that the number of needle insertions is associated with this symptom 25 . Currently, several strategies has been used to control post-dry needling soreness 26 .
In the case of our study, the SFR not only increases the ROM and improves CMJ height, but also reduced the pain significantly at 24 hrs. Previous results suggests there is an acute increase on the PPTs post-foam roller 27  It is important to highlight that, corroborating previous studies where the use of SRF was not associated with a decrease in strength and performance after its immediate application 28 , the use of DN seems to follow the same behavior after treatment on the variables studied in the present investigation. It seems, therefore, that, despite the tissue damage generated by DN, both techniques can be used to increase ankle dorsiflexion mobility and performance without an increase in magnitude and duration of acute post-treatment pain.
In addition, no adverse events were recorded during the study period.
Our study is not without limitations, which must be considered. Firstly, there is no significant differences between conditions, but it is possible to appreciate that there is a tendency in the post-intervention soreness in favour of SFR, being the small sample size

Ethics
The study adhered to the CONSORT guidelines 29 30  The zone one and two corresponded to the medial and lateral gastrocnemius, respectively.
The device was only applied at the muscular level, avoiding the Achilles tendon area and the popliteal fossa 15  Hong's fast-in and fast-out technique was implemented during the DN intervention 36 .
The needle was moved up and down 2-3 mm vertically through the latent MTrPS, which was located within the a muscle taut band 34 . Approximately 25 insertions without leaving the skin during half minute were implemented 32 . At the end of the intervention, a cotton piece was applied to the treated area for one minute to ensure an adequate control of hemostasis.

Post-intervention muscle soreness
Pressure pain sensibility (primary outocome), named also as pressure pain perception, is defined as the minimal amount of pressure at which the sense of pressure first changes to pain 37  The position used is shown in Figure 5. The PPTs was measured three times. The mean value from the 3 assessments was used in the analyses 41 . PPTs was assessed before and immediately after the needling procedure, and at 24 hours after intervention. Visual analogue scale this procedure has demonstrated good reliability 42 .
Ç Figure 5. Measurement of the pressure pain threshold at the MTrPs treated.

Weight-bearing lunge test
To evaluate ankle mobility, the weight-bearing lunge test was used. The participants lunged forward trying to touch a vertical line on the wall with their knee while maintaining the heel of the same limb evaluated in contact with the ground. They moved their foot away from the wall in order to reach maximum dorsiflexion ROM 43 . The foot of each participant was positioned so that the horizontal line on the base of the platform was between the 2nd and 3rd toes and bisected the calcaneus 44 . Participants were instructed to lunge their knee forward, keeping their heel in contact with the platform.
The subjects performed three familiarization trials followed by three test trials without rest interval between these two phases and between trials. The mean distance in cm of the three trials was recorded. During the test, the subjects were allowed to put the non-tested leg in a comfortable position behind the testing limb and to hold onto the wall to maintain their balance 45 . Participants were instructed to blend the ankle and knee as far as possible, but no encouragement was provided during the testing.

Countermovement jump
The CMJ jump height was measured with a light barrier system (OptoGait, Microgate, Bolzano Bozen, Italy) which has been used in similar studies 46  four jumps, two weeks before). Flight time was used to calculate the height of the rise using the body's centre of gravity 48 . The typically observed warm-up consisted of squatting movements, toe touches, hopping, and practice jumps, and lasted 3-5 minutes 49 . The average value of the three attempts was used for the subsequent analysis.

Statical Analysis
All variables were expressed as a mean and standard deviation (SD Pearson correlation coefficient was used to analyse the association between variables. A "trivial" association was established as r < 0.25, "small" between 0.25 < R < 0.50, "moderate to strong" between 0.50 < r < 0.75 and "very strong" as r > 0.75. The

CONCLUSIONS
Both SFR and DN are effective to improve ankle dorsiflexion and performance in healthy young male adults without generating an acute negative effect in muscle soreness. Then, both types of strategies could be used since the pain generated by both tools does not affect the performance and ankle dorsiflexion, although future studies with higher sample size and with different population are needed.

ACKNOWLEDGMENTS
We would like to thanks to all participants of the present study for their time.

AUTHOR CONTRIBUTIONS STATEMENT
V-M J and B-V L conceived and designed the experiment; L-S J, T-V J and GP conducted the experiment and collected the data; B IJ performed the statistical analysis. All authors wrote and reviewed the manuscript.

FUNDING
This research did not receive any funding from agencies in the public, private, or not-forprofit sectors.