Context: Previous authors suggest that lack of strength is an important risk factor for injuries in water polo. Hand-held dynamometers have potential as a clinical tool to measure strength, but they have not been validated in water polo players. Objective: The purpose of this study was to estimate intertrial variability and concurrent validity of hand-held dynamometer shoulder strength measurements in elite water polo players. Methods: A total of 19 male and 20 female elite water polo players performed isometric external (ER) and internal (IR) rotation strength tests against a hand-held dynamometer bilaterally in supine position with the shoulder in a 90–90 position. In addition, concentric IR and ER was captured at 90 deg/s with an isokinetic dynamometer, and torque values were determined near the 90–90 position. Main Outcome Measures: Spearman correlation coefficients were calculated for ER torque, IR torque, and ER/IR ratios between the devices. Two-way mixed-model intraclass correlations were used to assess intertrial variability. Results: Correlations between the devices were strong to very strong (ρ = .65–.82, P < .01) for absolute IR and ER but low for ER/IR ratios (ρ = .29, P = .07). There was less agreement at higher torque values. Intertrial variability was low with intraclass correlation values .88 to .93, P < .05. Conclusions: These results show that hand-held dynamometers are adequate clinical alternatives to measure absolute shoulder strength in water polo players. Stronger players may require stronger evaluators to resist the player’s push and obtain reliable results.
Félix Croteau, Shawn M. Robbins, and David Pearsall
Robert C. Lynall, Rachel S. Johnson, Landon B. Lempke, and Julianne D. Schmidt
Context: Reaction time is commonly assessed postconcussion through a computerized neurocognitive battery. Although this measure is sensitive to postconcussion deficits, it is not clear if computerized reaction time reflects the dynamic reaction time necessary to compete effectively and safely during sporting activities. Functional reaction time assessments may be useful postconcussion, but reliability must be determined before clinical implementation. Objective: To determine the test–retest reliability of a functional reaction time assessment battery and to determine if reaction time improved between sessions. Design: Cohort. Setting: Laboratory. Participants: Forty-one participants (21 men and 20 women) completed 2 time points. Participants, on average, were 22.5 (2.1) years old, 72.5 (11.9) cm tall, had a mass of 71.0 (13.7) kg, and were mostly right leg and hand dominant (92.7%). Interventions: Participants completed 2 clinical reaction time tests (computerized Stroop and drop stick) and 5 functional reaction time tests (gait, jump landing, single-leg hop, anticipated cut, and unanticipated cut) across 2 sessions. Drop stick and functional reaction time assessments were performed in single (motor task only) and dual task (motor task with cognitive task). Main Outcome Measures: Reaction time (in seconds) was calculated during all assessments. Test–retest reliability was determined using 2-way mixed-effects intraclass correlation coefficients (3, k). Paired samples t tests compared mean reaction time between sessions. Results: Test–retest reliability was moderate to excellent for all reaction time outcomes (intraclass correlation coefficients [3, k] range = .766–.925). Several statistically significant between-session mean differences were observed, but effect sizes were negligible to small (d range = 0.05–0.44). Conclusions: The functional reaction time assessment battery displayed similar reliability to the standard computerized reaction time assessment battery and may provide important postinjury information, but more research is needed to determine clinical utility.
Rodrigo Rodrigues Gomes Costa, Jefferson Rodrigues Dorneles, Guilherme Henrique Lopes, José Irineu Gorla, and Frederico Ribeiro Neto
Context: Monitoring training loads and consequent fatigue responses are usually a result of personal trainers’ experiences and an adaptation of methods used in sports for people without disabilities. Currently, there is little scientific evidence on the relationship between training load and fatigue resulting from training sessions in wheelchair sports. Analogous to the vertical jump, which has been associated with competitive performance and used to assess fatigue in Olympic sports, the medicine ball throw (MBT) is a fast, feasible, and accessible test that might be used to measure performance outcomes in Paralympic athletes. Objective: To test the MBT responsiveness to detect meaningful changes after training sessions in beginner wheelchair basketball players (WBP). Design: Cross-sectional study. Setting: Rehabilitation Hospital Network, Paralympic Program. Participants: Twelve male WBP. Main Outcomes Measures: The participants performed 3 consecutive days of training sessions involving exercises of wheelchair basketball skills, strength, and power. The MBT test was performed pre and post training sessions. Results: The smallest worthwhile change for MBT was 0.10 cm, and the lower and upper limits were 3.54 and 3.75 m, respectively. On the first day, the MBT started below the smallest worthwhile change lower limit and increased above the upper limit (3.53 and 3.78 m, respectively). On the second day, the MBT pretraining and posttraining session results were near the sample mean (3.62 and 3.59 m, respectively). On the third day, the WBP started the MBT test training higher than the upper limit (3.78 m) and decreased to near the mean (3.58 m). Conclusions: During 3 consecutive days of training sessions, the magnitude-based inference model presented meaningful changes in MBT test performance. The accurate association of the magnitude-based inference model with the MBT allows coaches and sports team staff to interpret the correct magnitude of change in WBP performance.
Clinical Scenario: Traditional loading (TL) is a common technique to employ when engaging in countermovement jumps (CMJ). Accentuated eccentric loading (AEL) is a newer modality that is being explored for acute CMJ performance. Focused Clinical Question: In adult, resistance-trained males, will AEL have a superior impact on acute CMJ performance compared to TL? Summary of Key Findings: The literature was searched for studies that examined the influence of AEL on acute CMJ performance compared to a TL protocol. TL was defined as any loading condition that utilized an equivalent resistance during both the eccentric and concentric contractions. Three studies met the inclusion and exclusion criteria, and were identified and included in the critically appraised topic. Each of the 3 studies found that various AEL conditions were either equal to or better than TL when examining subsequent CMJ performance. In no specific CMJ outcome measure was TL deemed to have a greater impact than AEL. Clinical Bottom Line: AEL provides more favorable acute CMJ performance than TL in adult, resistance-trained males. Strength of Recommendation: Consistent findings from 2 randomized crossover studies and one repeated-measured design investigation suggest level 2b evidence to support AEL as an ideal protocol for acute CMJ performance.
Craig R. Denegar and Justina Gray
Proprioceptive neuromuscular facilitation (PNF) stretching of the hamstrings improves flexibility but requires assistance from a clinician or partner. The original intent of our work was to assess the efficacy of self-assisted PNF hamstring stretching using a commercially available device. The authors observed improved flexibility in the stretched leg and, to a lesser extent, in the contralateral leg. While this was at first simply interesting, the finding became clinically relevant in the subsequent application in the care of a patient with low-back pain with radiating pain. This report provides study data and describes the translation of study findings into the care of a patient in a clinical setting.
Tomonari Takeshita, Hiroaki Noro, Keiichiro Hata, Taira Yoshida, Tetsuo Fukunaga, and Toshio Yanagiya
The present study aimed to clarify the effect of the foot strike pattern on muscle–tendon behavior and kinetics of the gastrocnemius medialis during treadmill running. Seven male participants ran with 2 different foot strike patterns (forefoot strike [FFS] and rearfoot strike [RFS]), with a step frequency of 2.50 Hz and at a speed of 2.38 m/s for 45 seconds on a treadmill with an instrumented force platform. The fascicle behavior of gastrocnemius medialis was captured using a B-mode ultrasound system with a sampling rate of 75 Hz, and the mechanical work done and power exerted by the fascicle and tendon were calculated. At the initial contact, the fascicle length was significantly shorter in the FFS than in the RFS (P = .001). However, the fascicular velocity did not differ between strike patterns. Higher tendon stretch and recoil were observed in the FFS (P < .001 and P = .017, respectively) compared with the RFS. The fascicle in the positive phase performed the same mechanical work in both the FFS and RFS; however, the fascicle in the negative phase performed significantly greater work in the FFS than in the RFS (P = .001). RFS may be advantageous for requiring less muscular work and elastic energy in the series elastic element compared with the FFS.
John H. Challis
Patricia R. Roby, Robert C. Lynall, Michael J. Cools, Stephen W. Marshall, Janna C. Fonseca, James R. Stevens, and Jason P. Mihalik
We report on hyperbaric oxygen (HBO2) therapy used to improve postinjury outcomes in eight acutely concussed high school student-athletes (5 males, 3 females, mean age = 16.0 ± 1.2 years). Patients were randomly assigned into one of three intervention groups: (a) HBO2 therapy; (b) hyperbaric therapy with compressed medical-grade air (HBA); or (c) normobaric 100% O2 therapy. All patients completed five 1-hr treatments within the first 10 days following his or her concussion. Main outcome measures included mental status examination, symptom burden, and the number of days from injury until the physician permitted the student-athlete to return to activity. Patients receiving HBO2 treatment experienced the greatest absolute symptom reduction over the five treatment sessions. No meaningful differences were found in mental status examination. All participants returned to activity in a similar timeframe. HBO2 therapy may be an effective option for the acute treatment of postconcussion symptoms, particularly in young athletes presenting with a high symptom burden.
Janie Cournoyer, David Koncan, Michael D. Gilchrist, and T. Blaine Hoshizaki
Understanding the relationship between head mass and neck stiffness during direct head impacts is especially concerning in youth sports where athletes have higher proportional head mass to neck strength. This study compared 2 neck stiffness conditions for peak linear and rotational acceleration and brain tissue deformations across 3 impact velocities, 3 impact locations, and 2 striking masses. A pendulum fitted with a nylon cap was used to impact a fifth percentile hybrid III headform equipped with 9 accelerometers and fitted with a youth American football helmet. The 2 neck stiffness conditions consisted of a neckform with and without resistance in 3 planes, representing the upper trapezius, the splenius capitis, and the sternocleidomastoid muscles. Increased neck stiffness resulted in significant changes in head kinematics and maximum principal strain specific to impact velocity, impact location, and striking mass.