Context: Measuring isometric shoulder rotational strength is clinically important for evaluating motor disability in athletes with shoulder injuries. Recent evidence suggests that handheld dynamometry may provide a low-cost and portable method for the clinical assessment of isometric shoulder strength. Objective: To investigate the concurrent validity and the intrarater and interrater reliability of handheld dynamometry for measuring isometric shoulder rotational strength. Design: Cross-sectional study. Setting: Biomechanics laboratory. Participants: Thirty-nine young, healthy participants. Main Outcome Measures: The peak isometric strength of the internal rotators and external rotators, measured by handheld dynamometry (in newton) and isokinetic dynamometry (in newton meter). Interventions: Maximal isometric shoulder rotational strength was measured as participants lay supine with 90° shoulder abduction, neutral rotation, 90° elbow flexion, and forearm pronation. Measurements were performed independently by 2 different physiotherapists and in 3 different sessions to evaluate interrater and intrarater reliability. The data obtained by handheld dynamometry were compared with those obtained by isokinetic testing to evaluate concurrent validity. Results: The intraclass correlation coefficients for interrater reliability in measuring maximum isometric shoulder external and internal rotation strength were .914 (95% confidence interval [CI], .842–.954) and .842 (95% CI, .720–.914), respectively. The intrarater reliability values of the method for measuring maximal shoulder external and internal rotation strength were 0.865 (95% CI, 0.757–0.927) and 0.901 (95% CI, 0.820–0.947), respectively. The Pearson correlation coefficients between the handheld and isokinetic dynamometer measurements were .792 (95% CI, .575–.905) for external rotation strength and .664 (95% CI, .419–.839) for internal rotation strength. Conclusions: The handheld dynamometer showed good to excellent reliability and moderate to good validity in measuring maximum isometric shoulder rotational strength. Therefore, handheld dynamometry could be acceptable for health and sports professionals in field situations to evaluate maximum isometric shoulder rotational strength.
Bin Chen, Lifen Liu, Lincoln Bin Chen, Xianxin Cao, Peng Han, Chenhao Wang, and Qi Qi
Richard Tahtinen, Hafrun Kristjansdottir, Daniel T. Olason, and Robert Morris
The aim of the study was to explore the prevalence of specific symptoms of depression in athletes and to test differences in the likelihood of athletes exhibiting these symptoms across age, sex, type of team sport, and level of competition. A sample of Icelandic male and female team sport athletes (N = 894, 18–42 years) was included in the study. Of the athletes exhibiting clinically significant depressive symptoms on the Patient Health Questionnaire-9, 37.5% did not exhibit core symptoms of depression. Compared with males, females were significantly more likely to exhibit depressed mood, feelings of worthlessness/guilt, and problems with sleep, fatigue, appetite, and concentration. Within males, differences were mostly related to neurovegetative aspects of depression (sleep and appetite), whereas in females, differences were related to cognitive/emotional aspects (e.g., depressed mood, guilt/worthlessness). The findings underline the importance of exploring specific symptoms of depression to provide a richer understanding of depressive symptomology in athletes.
Hannah L. Stedge and Kirk Armstrong
Clinical Scenario: Endurance sports require a great deal of physical training to perform well. Endurance training and racing stress the skeletal muscle, resulting in exercise-induced muscle damage (EIMD). Athletes attempt to aid their recovery in various ways, one of which is through compression. Dynamic compression consists of intermittent pneumatic compression (IPC) devices, such as the NormaTec Recovery System and Recovery Pump. Clinical Question: What are the effects of IPC on the reduction of EIMD in endurance athletes following prolonged exercise? Summary of Key Findings: The current literature was searched to identify the effects of IPC, and 3 studies were selected: 2 randomized controlled trials and 1 randomized cross-over study. Two studies investigated the effect of IPC on delayed onset muscle soreness and plasma creatine kinase in ultramarathoners. The other looked at the impact of IPC on delayed onset muscle soreness in marathoners, ultramarathoners, triathletes, and cyclists. All studies concluded IPC was not an effective means of improving the reduction of EIMD in endurance-trained athletes. Clinical Bottom Line: While IPC may provide short-term relief of delayed onset muscle soreness, this device does not provide continued relief from EIMD. Strength of Recommendation: In accordance with the Strength of Recommendation Taxonomy, the grade of B is recommended based on consistent evidence from 2 high-quality randomized controlled trials and 1 randomized cross-over study.
Enda Whyte, Tiarnán Ó Doinn, Miriam Downey, and Siobhán O’Connor
Context: Deficits in the hip range of motion are associated with hip and groin injuries. Accurate and reliable goniometric measurements are important in identifying those at risk of injury and determining the efficacy of treatment interventions. Smartphone goniometric applications are regularly used to assess joint ranges of motion; however, there is limited knowledge on the reliability of this method in relation to the hip, particularly between clinicians with different levels of experience. Objective: To determine the intratester and intertester reliability of a smartphone clinometer application for the assessment of hip goniometric measurements in healthy volunteers by an experienced and novice clinician. Design: Reliability study. Setting: University Athletic Therapy facility. Participants: Physically active, university students. Main Outcome Measures: The study determined the intra- and intertester (experienced vs novice clinician) reliability of goniometric measurements of the hip joint (modified Thomas test and seated hip internal and external rotation) using a smartphone goniometric application. Intraclass correlation coefficients (ICCs), standard error of measurement, and minimal detectable change at a 95% confidence interval were used to assess reliability. Results: Goniometric measurements demonstrated good to excellent relative intratester reliability for the modified Thomas test (ICC = .94), external rotation (ICC = .93–.95), and internal rotation (ICC = .80–.81). Intertester reliability for expert and novice clinicians was also excellent for the modified Thomas test (ICC = .98), external rotation (ICC = .95), and internal rotation (ICC = .92). Intratester and intertester standard error of measurement and minimal detectable change at 95% confidence interval values were similar for both testers and ranged from 1.9° to 3.6° and 5° to 10.1° and from 1.1° to 2.3° and 2.9° to 6.5°, respectively. Conclusion: Smartphone-based goniometric measurements of hip range of motion have high intratester and intertester reliability for novice and expert clinicians. It may be a useful, simple, and inexpensive resource for clinicians.
Keramat Ullah Keramat and Mohammad Naveed Babar
Context: Serratus anterior tightness is associated with scapular dyskinesis and overall shoulder dysfunction, which affects the range of motion. The most effective intervention to stretch the serratus anterior is unknown. Objective: To evaluate the effect of a therapist-administered novel serratus anterior stretch (SAS) on shoulder range of motion. Method: This study recruited 30 healthy subjects of age 21.20 (1.69) years, height 1.65 (0.11) m, and weight 60.90 (10.36) kg in equal ratio of males and females who scored 1 or 2 on the shoulder mobility test of functional movement screening. A single intervention of a novel SAS was applied to the shoulder. Outcome variables before and after the SAS included the following: shoulder ROM (flexion, abduction, internal rotation, and external rotation) and functional movements of reaching up behind the back and reaching down behind the neck. Results: A paired t test was used to analyze the data. Following the acute SAS intervention, all shoulder ROM improved significantly (P < .000). The change in internal rotation was 6.00° (7.47°), external rotation was 5.66° (9.35°), abduction was 13.50° (11.82°), flexion was 20° (13.33°), reaching up behind the back was 5.10 (2.21) cm, and reaching down behind the neck was 5.41 (2.89) cm. The most marked improvement was in reaching up behind the back (24.48%) and reaching down behind the neck (22.78%). A very large effect size (>1) was observed across most of the variables. Conclusion: An acute SAS intervention improves shoulder mobility in healthy individuals. It is recommended for the trial on the prevention and rehabilitation of shoulder pathologies with restriction in shoulder mobility.
Hannah W. Tucker, Emily R. Tobin, and Matthew F. Moran
Context: Performance on single-leg hopping (SLH) assessments is commonly included within return-to-sport criteria for rehabilitating athletes. Triaxial accelerometers have been used to quantify impact loading in a variety of movements, including hopping; however, they have never been attached to the tibia during SLH, and their method of fixation has not been investigated. Objective: The purpose of this study was to quantify triaxial accelerations and evaluate the influence of the fixation method of a lightweight inertial measurement unit (Blue Trident) mounted to the tibia during SLH performance. Design: Single cohort, repeated-measures experimental design. Participants: Sixteen healthy participants (10 females and 6 males; 20 [0.9] y; 1.67 [0.08] m; 66.0 [8.5] kg) met the inclusion criteria, volunteered, and completed this study. Interventions: Participants performed 2 sets of 3 SLH trials with an inertial measurement unit (1500 Hz) fixated to the tibia, each set with 1 of 2 attachment methods (double-sided tape [DST] with athletic tape and silicon strap [SS] with Velcro adhesion). Main Outcome Measures: Hop distance, peak tibial acceleration (PTA), time to PTA, and the acceleration slope were assessed during each hop landing. Results: Repeated-measures analysis of variance determined no significant effect of the attachment method on hop metrics (P = .252). Across 3 trials, both fixation methods (DST and SS) had excellent reliability values (intraclass correlation coefficient: .868–.941) for PTA and acceleration slope but not for time to PTA (intraclass correlation coefficient: .397–.768). The PTA for DST (27.22 [7.94] g) and SS (26.21 [10.48] g) was comparable and had a moderate, positive relationship (DST: r = .72, P < .01; SS: r = .77, P < .01) to SLH distance. Conclusions: Tibial inertial measurement units with triaxial accelerometers can reliably assess PTA during performance of the SLH, and SS is a viable alternative tibial attachment to DST.
Daichi Tomita, Tadashi Suga, Hiromasa Ueno, Yuto Miyake, Takahiro Tanaka, Masafumi Terada, Mitsuo Otsuka, Akinori Nagano, and Tadao Isaka
This study examined the relationship between Achilles tendon (AT) length and 100-m sprint time in sprinters. The AT lengths at 3 different portions of the triceps surae muscle in 48 well-trained sprinters were measured using magnetic resonance imaging. The 3 AT lengths were calculated as the distance from the calcaneal tuberosity to the muscle–tendon junction of the soleus, gastrocnemius medialis, and gastrocnemius lateralis, respectively. The absolute 3 AT lengths did not correlate significantly with personal best 100-m sprint time (r = −.023 to .064, all Ps > .05). Furthermore, to minimize the differences in the leg length among participants, the 3 AT lengths were normalized to the shank length, and the relative 3 AT lengths did not correlate significantly with personal best 100-m sprint time (r = .023 to .102, all Ps > .05). Additionally, no significant correlations were observed between the absolute and relative (normalized to body mass) cross-sectional areas of the AT and personal best 100-m sprint time (r = .012 and .084, respectively, both Ps > .05). These findings suggest that the AT morphological variables, including the length, may not be related to superior 100-m sprint time in sprinters.
Justine J. Reel
Corey A. Pew, Sarah A. Roelker, Glenn K. Klute, and Richard R. Neptune
The coupling between the residual limb and the lower-limb prosthesis is not rigid. As a result, external loading produces movement between the prosthesis and residual limb that can lead to undesirable soft-tissue shear stresses. As these stresses are difficult to measure, limb loading is commonly used as a surrogate. However, the relationship between limb loading and the displacements responsible for those stresses remains unknown. To better understand the limb motion within the socket, an inverse kinematic analysis was performed to estimate the motion between the socket and tibia for 10 individuals with a transtibial amputation performing walking and turning activities at 3 different speeds. The authors estimated the rotational stiffness of the limb-socket body to quantify the limb properties when coupled with the socket and highlight how this approach could help inform prosthetic prescriptions. Results showed that peak transverse displacement had a significant, linear relationship with peak transverse loading. Stiffness of the limb-socket body varied significantly between individuals, activities (walking and turning), and speeds. These results suggest that transverse limb loading can serve as a surrogate for residual-limb shear stress and that the setup of a prosthesis could be individually tailored using standard motion capture and inverse kinematic analyses.