Author Names
Jusdado-Garcia, M & Cuesta-Barriuso, R
Reviewer Name
Megan Benzie, SPT, B.S.
Reviewer Affiliation(s)
Duke University School of Medicine, Doctor of Physical Therapy Division
Paper Abstract
The shoulder in CrossFit should have a balance between mobility and stability. Glenohumeral internal rotation deficit and posterior shoulder stiffness are risk factors for overhead shoulder injury. Objective. To determine the effectiveness of instrument-assisted soft tissue mobilization and horizontal adduction stretch in CrossFit practitioners’ shoulders. Methods: Twenty-one regular CrossFitters were allocated to experimental (stretching with isometric contraction and instrument-assisted soft tissue mobilization) or control groups (instrument-assisted soft tissue mobilization). Each session lasted 5 min, 2 days a week, over a period of 4 weeks. Shoulder internal rotation and horizontal adduction (digital inclinometer), as well as posterior shoulder stretch perception (Park scale), were evaluated. Shapiro–Wilk test was used to analyze the distribution of the sample. Parametric Student’s t-test was used to obtain the intragroup differences. The inter- and intra-rater differences were calculated using a repeated measures analysis of variance (ANOVA). Results. Average age was 30.81 years (SD: 5.35), with an average height of 178 (SD: 7.93) cm and average weight of 82.69 (SD: 10.82) kg. Changes were found in the experimental group following intervention (p < 0.05), and when comparing baseline and follow-up assessments (p < 0.05) in all variables. Significant differences were found in the control group following intervention (p < 0.05), in right horizontal adduction and left internal rotation. When comparing the perception of internal rotation and horizontal adduction in both groups, significant differences were found. Conclusions. Instrument-assisted soft tissue mobilization can improve shoulder horizontal adduction and internal rotation. An instrument-assisted soft tissue mobilization technique yields the same results alone as those achieved in combination with post-isometric stretch with shoulder adduction.
NIH Risk of Bias Tool
Quality Assessment of Case-Control Studies
- Was the research question or objective in this paper clearly stated and appropriate?
- Yes
- Was the study population clearly specified and defined?
- Yes
- Did the authors include a sample size justification?
- Yes
- Were controls selected or recruited from the same or similar population that gave rise to the cases (including the same timeframe)?
- Yes
- Were the definitions, inclusion and exclusion criteria, algorithms or processes used to identify or select cases and controls valid, reliable, and implemented consistently across all study participants?
- Yes
- Were the cases clearly defined and differentiated from controls?
- Yes
- If less than 100 percent of eligible cases and/or controls were selected for the study, were the cases and/or controls randomly selected from those eligible?
- Yes
- Was there use of concurrent controls?
- No
- Were the investigators able to confirm that the exposure/risk occurred prior to the development of the condition or event that defined a participant as a case?
- Yes
- Were the measures of exposure/risk clearly defined, valid, reliable, and implemented consistently (including the same time period) across all study participants?
- No
- Were the assessors of exposure/risk blinded to the case or control status of participants?
- No
- Were key potential confounding variables measured and adjusted statistically in the analyses? If matching was used, did the investigators account for matching during study analysis?
- Yes
Key Finding #1
Athletes training CrossFit more than four days a week without regular “physiotherapeutic care” were associated with higher musculoskeletal injury rates, with a high incidence in shoulder injuries specifically.
Key Finding #2
Glenohumeral joint stability depends, in large part, on active stability. The muscle fatigue that is caused by typical CrossFit workouts can have a detrimental effect on the amount of stability the joint can provide. This fatigue increases the likelihood of injury.
Key Finding #3
This study is limited in that the control group received soft tissue mobilizations, which the experimental group received instrument assisted soft tissue techniques and post isometric holds. With two variables being changed, it is impossible to determine if it was the instrument assisted device or the isometric holds that made the impact on the range of motion.
Key Finding #4
This study had significantly more males than females (19:2), which may indicate that the results are not transferable to all patients.
Please provide your summary of the paper
This randomized, single blind pilot study looked at the effect of either soft tissue mobilizations alone or instrument-assisted soft tissue techniques in addition to post-isometric horizontal adduction stretches on CrossFit athlete’s shoulder internal rotation, horizontal adduction, and the perception of the stretching of the back of the shoulder with each. The study excluded participants who had a shoulder injury in the past three months or had a shoulder surgery in the last six months. Due to this, these results are not as applicable to the injured population. The interventions were provided twice a week for four weeks. The soft tissue mobilizations were applied for 20 seconds in the parallel direction and 20 seconds in the perpendicular direction on the posterior shoulder. Most studies agree that three sets of 30 seconds are most beneficial for manual therapy techniques, so this may have impacted their results. However, this study did note that for instrument assisted techniques, they were able to use less time, 40 seconds compared to the typical 90 seconds, per stretch and yield the same result. The instrument assisted group achieved significant (p < 0.05) improvements in all variables measured and continued at the four week follow up mark. The control group also showed improvements (p < 0.05) in right horizontal adduction and left internal rotation. This study was limited in that there was a small sample size and participants were excluded if they experienced current or recent shoulder pain, which limits its ability to be applied to the clinical population. Additionally, this study did not look at if these positive effects last longer than four weeks after the final intervention session.
Please provide your clinical interpretation of this paper. Include how this study may impact clinical practice and how the results can be implemented.
This study does suggest that manual therapy, specifically instrument assisted soft tissue work, may benefit CrossFit athletes in shoulder range of motion. This may help clinicians in decision making for a plan of care. However, this study was limited by protocol itself being not specific, short treatment times, and small subject groups. More research needs to be done on the injured shoulder for CrossFitters, in addition to the long term affects and maintenance of shoulder range of motion with treatments.
