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.
Daniel J. Davis and John H. Challis
Time-differentiating kinematic signals from optical motion capture amplifies the inherent noise content of those signals. Commonly, biomechanists address this problem by applying a Butterworth filter with the same cutoff frequency to all noisy displacement signals prior to differentiation. Nonstationary signals, those with time-varying frequency content, are widespread in biomechanics (eg, those containing an impact) and may necessitate a different filtering approach. A recently introduced signal filtering approach wherein signals are divided into sections based on their energy content and then Butterworth filtered with section-specific cutoff frequencies improved second derivative estimates in a nonstationary kinematic signal. Utilizing this signal-section filtering approach for estimating running vertical ground reaction forces saw more of the signal’s high-frequency content surrounding heel strike maintained without allowing inappropriate amounts of noise contamination in the remainder of the signal. Thus, this signal-section filtering approach resulted in superior estimates of vertical ground reaction forces compared with approaches that either used the same filter cutoff frequency across the entirety of each signal or across the entirety of all signals. Filtering kinematic signals using this signal-section filtering approach is useful in processing data from tasks containing an impact when accurate signal second derivative estimation is of interest.