Context: An imbalance between shoulder internal rotation (IR) and external rotation (ER) strength in athletes is proposed to increase the risk of sustaining a shoulder injury. Hand-held (HHD) and externally fixed dynamometry are reliable forms of assessing shoulder IR and ER strength. A new externally fixed device with an attachable fixed upper-limb mold (The ForceFrame) exists; however, its reliability in measuring shoulder strength is yet to be investigated. Objective: To determine the test–retest reliability of the ForceFrame, with and without the fixed upper-limb mold, in the assessment of shoulder IR and ER strength, as compared with HHD. Design: Test–retest reliability study. Setting: Laboratory, clinical. Participants: Twenty-two healthy and active individuals were recruited from the university community and a private physiotherapy practice. Main Outcome Measures: Maximal isometric shoulder IR and ER strength was measured using the ForceFrame and traditional HHD in neutral and at 90° shoulder abduction. Mean (SD) strength measures were calculated. Test–retest reliability was analyzed using intraclass correlation coefficients (3, 1). The SEM and minimal detectable change were calculated. Results: Good to excellent test–retest reliability was found for all shoulder strength tests across HDD and ForceFrame dynamometry (intraclass correlation coefficients [3, 1] = .854–.916). The minimal detectable changes ranged between 25.61 and 41.84 N across tests. Test–retest reliability was not affected by the dynamometer or testing position. Conclusions: The results from this study indicate that both the ForceFrame and HHD are suitable for measuring shoulder strength in clinical practice. The use of the fixed upper-limb mold with the ForceFrame does not improve reliability.
Jamon Couch, Marc Sayers, and Tania Pizzari
David Rhodes, Jill Alexander, and Matt Greig
Background: Rising injury rates within football require further understanding of the etiological risk factors associated with lower-limb injury. Aim: To examine the temporal pattern of recovery of directional dynamic stability measures post football-specific fatigue. Methods: Eighteen male elite footballers completed baseline assessments of directional dynamic stability measures (Overall Stability Index, anterior–posterior stability [A-P], medial–lateral stability [M-L] on level 1 of the Biodex Stability System). Post Soccer-Specific Aerobic Field Test90 measures were repeated immediately, +24 hours, +48 hours, and +72 hours. The main effects for the recovery time and direction of stability were supplemented by regression modeling to describe the temporal pattern of recovery. Results: Significant main effects for time were identified for all directions of stability (Overall Stability Index, A-P, and M-L) up to +48 hours postexercise (P ≤ .05). The quadratic pattern of temporal recovery highlights a minimum of 37.55 to 38.67 hours and maximum of 75.09 to 77.33 hours. Additionally, a main effect for direction of stability was observed, with significant differences identified between A-P and M-L stability at all time points (P ≤ .001). Conclusions: Reductions in directional dynamic stability +48 hours postfatigue highlight implications for training design, recovery strategies, and injury management for performance practitioners. Interestingly, A-P stability has been highlighted as being significantly reduced compared with M-L stability at all time points, regardless of the fatigue exposure. Practitioners should consider the reduction of stability in this plane in relation to common mechanisms of injury in the knee to inform injury–risk-reduction strategies.
Nickolai J.P. Martonick, Ashley J. Reeves, James A. Whitlock, Taylor C. Stevenson, Scott W. Cheatham, Craig P. McGowan, and Russell T. Baker
Context: Instrument-assisted Soft Tissue Mobilization (IASTM) is a therapeutic intervention used by clinicians to identify and treat myofascial dysfunction or pathology. However, little is known about the amount of force used by clinicians during an IASTM treatment and how it compares to reports of force in the current literature. Objective: To quantify the range of force applied by trained clinicians during a simulated IASTM treatment scenario. Design: Experimental. Setting: University research laboratory. Participants: Eleven licensed clinicians (physical therapist = 2, chiropractor = 2, and athletic trainer = 7) with professional IASTM training participated in the study. The participants reported a range of credentialed experience from 1 to 15 years (mean = 7 [4.7] y; median = 6 y). Intervention: Participants performed 15 one-handed unidirectional sweeping strokes with each of the 5 instruments for a total of 75 data points each. Force data were collected from a force plate with an attached skin simulant during a hypothetical treatment scenario. Main Outcome Measures: Peak force and average forces for individual strokes across all instruments were identified. Averages for these forces were calculated for all participants combined, as well as for individual participants. Results: The average of peak forces produced by our sample of trained clinicians was 6.7 N and the average mean forces was 4.5 N. Across individual clinicians, average peak forces ranged from 2.6 to 14.0 N, and average mean forces ranged from 1.6 to 10.0 N. Conclusions: The clinicians in our study produced a broad range of IASTM forces. The observed forces in our study were similar to those reported in prior research examining an IASTM treatment to the gastrocnemius of healthy individuals and greater than what has been reported as effective in treating delayed onset muscle soreness. Our data can be used by researchers examining clinically relevant IASTM treatment force on patient outcomes.
Andreia Pereira, Cátia Teixeira, Karla Pereira, Leandro Ferreira, Maria Marques, and Anabela G. Silva
Context: Neural mobilization is commonly used in sports, and previous studies have suggested that it has a positive impact on lower-limb flexibility and performance. However, studies exploring the effect of neural mobilization dosage are almost nonexistent. Objectives: This study aimed to assess whether 2 distinct dosages of neural gliding mobilization (4 and 8 sets of 10 repetitions) impact the flexibility and performance of both the mobilized and nonmobilized lower limb in basketball athletes differently. Design: Randomized, parallel, and single-blinded study. Setting: Amateur and professional basketball clubs. Participants: Fifty-two basketball athletes (40 men and 12 women), who were distributed into 2 groups; one received 40 (n = 28) and the other 80 repetitions (n = 24) of neural gliding mobilization. Intervention: Neural gliding mobilization applied to a single limb (the dominant limb). Main Outcome Measures: Knee extension angle for hamstring flexibility; hop tests and single-leg vertical jump for performance. Results: There was a significant main effect of time (P < .001), a significant interaction between time and limb for flexibility (P = .003), and a significant interaction between time and limb for the single-leg hop test (P = .032). No other significant main effect for any of the remaining variables was found (P > .05). Conclusions: The application of both 40 repetitions and 80 of neural gliding significantly improved lower-limb flexibility, and one was not superior to the other. Neither one dosage nor the other positively or negatively impacted the lower-limb performance of basketball athletes.
Romana Brunner, Mario Bizzini, Nicola A. Maffiuletti, and Karin Niedermann
Context: Injury prevention programs for the lower extremities are effective in team-sport athletes. Objective: To identify barriers and facilitators among professional ice hockey players and staff members for adhering to an injury prevention program. Design: Cross-sectional survey. Setting and Participants: A questionnaire about barriers and facilitators related to knowledge/perceptions, beliefs, adoption, and habits about injury prevention was filled out by Swiss professional male ice hockey players and staff members. Main Outcome Measures: Frequencies of ratings were calculated and binary logistic regression analysis was applied to predict a relationship between a high/low perceived benefit of an injury prevention program and player characteristics. Results: Knowledge, perceived benefit, and relevance of injury prevention as well as awareness of high risk of injuries in ice hockey were identified as important facilitators. Players’ habit of exercise performance was identified as a barrier. Program understanding of staff members was identified as a facilitator and barrier. No significant relationships were observed between a high/low perceived benefit of an injury prevention program and age (P = .85), nationality (P = .53), level of education (P = .63), National League experience (P = .50), or occurrence of lower-extremity injuries in the previous season (P = .10). Conclusions: Players and staff members clearly rated perceived benefits of an injury prevention program, which can be considered an important facilitator of the uptake and adoption of such a program in ice hockey teams. Players should be educated about well-performed injury prevention exercises. Staff members should be educated about the aim of a regular injury prevention program. An injury prevention program might be implemented in players of all ages, levels of education, and experience in the National League, irrespective of previous injuries. Identified barriers and facilitators should be addressed when implementing an injury prevention program in a setting of professional ice hockey teams in the future.
Shannon L. Mihalko, Phillip Cox, Edward Ip, David F. Martin, Paul DeVita, Monica Love, Santiago Saldana, D. Wayne Cannon, Rebecca E. Fellin, Joseph F. Seay, and Stephen P. Messier
Context: While 55 million Americans incorporate running into their exercise routines, up to 65% of runners sustain an overuse injury annually. It has been consistently shown that regular physical activity positively impacts quality of life (QOL), an essential public health indicator; however, the impact of running-related injuries on QOL is unknown. This study seeks to determine whether overuse injury severity impacts QOL in recreational runners, and if self-efficacy mediates this relationship. Design: Community-based prospective cohort study of 300 runners who had been running injury free for at least 5 miles/wk in the past 6 months. Methods: Self-efficacy for running and QOL measures (Short Form-12 Physical Component and Mental Component, Satisfaction with Life, Positive Affect and Negative Affect) were assessed at baseline, time of injury, and follow-up visits. Over 2 years of observation, overuse injuries were diagnosed by an orthopedic surgeon and injured runners were referred to a physical therapist. Results: Injury severity was significantly (P < .01) related with 2 indices of QOL, such that the effect of injury severity was −2.28 units on the Short Form-12 physical component and −0.73 units on positive affect. Self-efficacy accounted for 19% and 48% of the indirect effects on Short Form-12 physical component and positive affect, respectively. Conclusions: Since self-efficacy is a modifiable factor related to decreased QOL, these findings have important clinical implications for rehabilitation interventions.
Shana E. Harrington, Sean McQueeney, and Marcus Fearing
Context: Training loads, injury, and injury prevention in the Para sports population has not been well established. Objective: The purpose of this study was to survey elite-level swimming, cycling, and athletic Para sport athletes in the United States who were competing in the 2016 US Paralympic trials to better understand common injuries among athletes in each sport and to determine whether injury prevention programs were being utilized. Design: Cross-sectional, survey study. Setting: The 2016 US Paralympic trials for swimming, cycling, and athletics. Participants: Athletes who competed in swimming, cycling, and/or athletics at the 2016 US Paralympic trials (N = 144; 83 males and 61 females). Main Outcome Measures: Participants completed electronic survey using Qualtrics XM (Qualtrics, Provo, UT) with questions pertaining to average number of hours trained per week, number of cross-training hours performed each week, descriptive information regarding sport-related injuries, pain, whether athletes received treatment for injuries, and descriptive information regarding whether the athletes had participated in an injury prevention program. Results: Over 64% of respondents reported training greater than or equal to 11 hours per week, and 45% of athletes reported spending greater than or equal to 6 hours per week cross-training. Forty-two percent of athletes reported currently having pain with 34% reporting missing a competition because of injury. Only 24% of respondents reported having participated in an injury prevention program. Conclusions: Many Para sport athletes train at similar durations as able-bodied counterparts and have pain that interferes with their ability to train and compete, however, only a small percentage consistently perform injury prevention programs.
Soo-Yong Kim, Jae-Seop Oh, and Min-Hyeok Kang
Context: Asymmetrical movements of trunk and lower-extremity are common during the bridge exercise on the unstable condition. However, no studies have investigated whether visual biofeedback of pressing pressure on the unstable surface changes muscle activation patterns of trunk and hip extensors and pelvic rotation during the bridge exercise. Objective: To investigate how visual biofeedback of pressing pressure influences symmetrical activity of lumbar and hip extensor and pelvic rotation. Design: Cross-sectional study. Setting: Laboratory. Participants: Twenty healthy males participated in this study. Interventions: The participants performed 2 versions of the bridge exercise: the standard bridge exercise and the bridge exercise with visual biofeedback using amount of pressing pressure on the sling. Main Outcome Measures: Surface electromyography was used to measure the symmetry (ie, the difference between dominant and nondominant sides) of muscle activation in the bilateral erector spinae, gluteus maximus, and hamstring muscles, and motion sensors were used to assess pelvic rotation. Symmetry of pressing pressure was measured using a tension meter. Results: The differences between the dominant and nondominant pressing pressures and differences between the electromyography activity of the dominant and nondominant erector spinae, gluteus maximus, and hamstring were significantly smaller during the bridge exercise with visual biofeedback than during the standard bridge exercise (P < .05). In addition, there was significantly less pelvic rotation during the bridge exercise with visual biofeedback than during the standard bridge exercise (P < .05). Conclusions: The present findings suggest that visual biofeedback strategy may be a useful method for enhancing the symmetrical activation of the erector spinae, gluteus maximus, and hamstring and for reducing pelvic rotation during the bridge exercise on the unstable surface.
Gabriel dos Santos Oliveira, João Breno de Araujo Ribeiro-Alvares, Felipe Xavier de Lima-e-Silva, Rodrigo Rodrigues, Marco Aurélio Vaz, and Bruno Manfredini Baroni
Context: Eccentric knee flexor strength assessments have a key role in both prevention and rehabilitation of hamstring strain injuries. Objective: To verify the reliability of a clinical test for measuring eccentric knee flexor strength during the Nordic hamstring exercise using a commercially available handheld dynamometer. Design: Reliability study. Setting: Physical Therapy Laboratory, Federal University of Health Sciences of Porto Alegre (Brazil). Participants: Fifty male amateur athletes (soccer or rugby players; 24  y). Main Outcome Measures: Eccentric knee flexor strength. Results: When compared with a load cell–based device, the clinical test using a handheld dynamometer provided smaller force values (P < .05) with large effect sizes (.92–1.21), moderate intraclass correlation (.60–.62), typical error of 30 to 31 N, and coefficient of variation of 10% to 11%. Regarding the test–retest reproducibility (2 sessions separated by 1 week), the clinical test provided similar force values (P > .05) with only small effect sizes (.20–.27), moderate to good correlation (.67–.76), typical error of 23 to 24 N, and coefficient of variation of 9% to 10%. Conclusion: The clinical test with handheld dynamometer proposed by this study can be considered an affordable and relatively reliable tool for eccentric knee flexor strength assessment in the clinical setting, but results should not be directly compared with those provided by load cell–based devices.
Aaron Byrne, Clare Lodge, and Jennifer Wallace
Context: Single-leg stability has been associated with injury risk and is a key component of many injury prevention interventions. Methods of measuring single-leg stability are varied yet often unreliable. Objective: To establish within- and between-day test–retest reliability for single-leg time to stabilization (SL-TTS) following a drop-landing maneuver of 20 cm in height among a healthy cohort. Design: Test–retest reliability study. Setting: Healthy cohort from a third-level educational institution. Participants: Nineteen (11 females and 8 males) healthy individuals. Main Outcome Measures: The SL-TTS in the vertical plane. Results: The SL-TTS showed good within-day (intraclass correlation coefficient = .715) and excellent between-day (intraclass correlation coefficient = .83) test–retest reliability. The minimal detectable change was calculated as 171.6 ms for within-day contexts and 123.8 ms for between-day contexts. Conclusions: This method of measuring SL-TTS is reliable and could be used to detect changes over time in a healthy cohort. This could be of value to clinicians in injury risk factor identification or assessing the effectiveness of single-leg stability training. However, further research is needed to investigate its reliability in pathological populations.