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Can We Just Play? Internal Validity of Assessing Physiological State With a Semistandardized Kicking Drill in Professional Australian Football

Adriano Arguedas-Soley, Tzlil Shushan, Andrew Murphy, Nicholas Poulos, Ric Lovell, and Dean Norris

Purpose: To examine associations between exercise heart rate (HRex) during a continuous-fixed submaximal fitness test (CF-SMFT) and an intermittent-variable protocol (semistandardized kicking drill [SSD]) in Australian Football athletes, controlling for external intensities, within-session scheduling, and environmental conditions. Methods: Forty-four professional male Australian Football athletes (22.8 [8.0] y) were monitored over 10 sessions involving a 3-minute CF-SMFT (12 km·h−1) as the first activity and a SSD administered 35.7 (8.0) minutes after the CF-SMFT. Initial heart rate and HRex were collected, with external intensities measured as average velocity (in meters per minute) and average acceleration–deceleration (in meters per second squared). Environmental conditions were sampled. A penalized hierarchical linear mixed model was tuned for a Bayesian information criterion minima using a 10-fold cross-validation, with out-of-sample prediction accuracy assessed via root-mean-squared error. Results: SSD average acceleration–deceleration, initial heart rate, temperature, and ground hardness were significant moderators in the tuned model. When model covariates were held constant, a 1%-point change in SSD HRex associated with a 0.4%-point change in CF-SMFT HRex (95% CI, 0.3–0.5). The tuned model predicted CF-SMFT HRex with an average root-mean-squared error of 2.64 (0.57) over the 10-fold cross-validation, with 74% and 86% of out-of-sample predictions falling within 2.7%-points and 3.7%-points, respectively, from observed values, representing the lower and upper limits for detecting meaningful changes in HRex according to the documented typical error. Conclusions: Our findings support the use of an SSD to monitor physiological state in Australian Football athletes, despite varied scheduling within session. Model predictions of CF-SMFT HRex from SSD HRex closely aligned with observed values, considering measurement imprecision.

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Changes in Hip Isometric Strength of Female College Soccer Players After High-Workload Training Session

Maxine Furtado Mesa, Jeffrey R. Stout, L. Colby Mangum, Kyle S. Beyer, Michael J. Redd, and David H. Fukuda

Context: The hip adductor and abductor muscles play vital roles as stabilizers in the lower-extremity. Their activation during soccer-specific actions is essential, but local muscular fatigue can hinder athletic performance and increase the risk of injury. Design: This study aimed to observe the variations in frontal plane hip strength in female college soccer players before and after a high-workload soccer-specific training session. Furthermore, the study sought to compare the relative changes in hip strength with the internal and external load measures obtained during that session. Methods: Twenty female college soccer players participated in a retrospective observational study. Isometric hip adductor and abductor strength were measured before and after a training session in the college spring season. Measurements were taken with a handheld dynamometer (MicroFET 2) while the players were supine. Global positioning system sensors (Catapult Vector S7), commonly worn by players during training sessions and competitive matches, were used to measure external and internal loads. Statistical analyses were performed using paired samples t test to assess hip adductor and abductor strength changes before and after the training session. Spearman rank was used to identify correlation coefficients between global positioning system data and isometric hip strength. Results: The findings revealed significant decreases in the strength of the right hip adduction (P = .012, −7% relative change), right abduction (P = .009, −7.6% relative change), and left abduction (P = .016, −4.9% relative change) after the training session. Furthermore, relative decreases in hip isometric adduction and abduction strength are related to the distance covered at high speeds. Conclusion: The results of this study highlight that hip isometric adduction and abduction strength tend to decrease after exposure to high workloads during soccer-specific training.

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Does a Hip Muscle Activation Home Exercise Program Change Movement Patterns on the Forward Step-Down Test?

Erin McCallister, Caroline Hughs, Mia Smith, and Daniel W. Flowers

Context: Poor knee biomechanics contribute to knee joint injuries. Neuromuscular control over knee position is partially derived from the hip. It is unknown whether isolated activation training of the gluteal muscles improves lower-extremity frontal plane mechanics. This study examined if a home-based hip muscle activation program improves performance on the Forward Step-Down Test as well as increases surface electromyography (sEMG) activation of the gluteal muscles. Design: The study utilized a single-group repeated-measures design. Methods: Thirty-five participants (24 females, mean age = 23.17 [SD 1.36] years) completed an 8-week hip muscle activation program. The Forward Step-Down Test score and sEMG of gluteus maximus and medius were assessed preintervention and postintervention. Results: Forward Step-Down Test scores improved significantly from preintervention (Mdn = 3.5) to postintervention (Mdn = 3.0, T = 109, P = .010, r = .31.), but this result did not meet clinical significance. sEMG analysis revealed a significant increase in mean gluteus maximus activation (P = .028, d = 1.19). No significant dose–response relationship existed between compliance and the Forward Step-Down Test scores or sEMG results. Conclusions: A home-based hip activation program increases gluteus maximus activation without clinically significant changes in frontal plane movement quality. Future studies may find clinical relevance by adding motor learning to the activation training program to improve functional muscle use.

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Effectiveness of Platelet-Rich Plasma in Reducing Pain and Increasing Function After Acute Lateral Ankle Sprain: A Critically Appraised Topic

Erin Frey, Christopher D. Brown, and Brady Tripp

Clinical Scenario: Ankle sprains are one of the most common injuries in athletics, and many lead to recurrent sprains, chronic ankle instability, and persistent symptoms. Treatment improvements are needed. Platelet-rich plasma (PRP) involves formulating autologous plasma with higher platelet concentration to be injected in the desired tissue. There is currently high-quality evidence supporting the use of PRP with lateral epicondylitis and knee osteoarthritis to accelerate the healing process and decrease pain. Clinical Question: Does the injection of PRP relieve pain faster and improve function compared with no injection or placebo in patients with a lateral ankle sprain? Summary of Key Findings: A computerized search yielded 191 studies; of these, 3 studies fit the inclusion and exclusion criteria. PRP injection reduces pain and increases function after lateral ankle sprain 5 to 8 weeks after intervention. Clinical Bottom Line: The use of PRP after lateral ankle sprain to decrease pain and increase function is supported with moderate evidence. Strength of Recommendation: Based on the Strength of Recommendation Taxonomy, evidence from the included studies is considered as level B, reflecting limited quality patient-oriented evidence.

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The Effects of Augmenting Balance Training with Stroboscopic Goggles on Postural Control in Chronic Ankle Instability Patients: A Critically Appraised Topic

Joshua S. Mohess, Hyunwook Lee, Serkan Uzlaşir, and Erik A. Wikstrom

Clinical Scenario: Individuals with chronic ankle instability (CAI) typically complete balance training protocols to improve postural control and reduce recurrent injury risk. However, the presence of CAI persists after traditional balance training protocols suggesting that such programs may be missing elements that could be beneficial to patients. Visual occlusion modalities, such as stroboscopic goggles, may be able to augment balance training exercises to further enhance postural control gains in those with CAI. However, a cumulative review of the existing evidence has yet to be conducted. Focused Clinical Question: Does wearing stroboscopic goggles during balance training result in greater improvements to postural control than balance training alone in those with CAI? Summary of Key Findings: All 3 studies indicated that the stroboscopic goggles group had statistically significant improvements in either a measure of static or dynamic postural control relative to the standard balance training group. However, significant improvements were not consistent across all postural control outcomes assessed in the included studies. Clinical Bottom Line: Postural control may improve more in those with CAI when stroboscopic goggles were worn while completing balance training exercises relative to completing balance training exercises alone. Strength of Recommendation: Overall, consistent moderate- to high-quality evidence was present in the 3 studies, suggesting grade C evidence for the use of stroboscopic goggles during balance training in those with CAI.

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Respiratory Muscle Training in Para-Athletes: A Systematic Review on the Training Protocols and Effects on Reported Outcomes

Buket Akinci, Cigdem Emirza Cilbir, Ahmet Kocyigit, and Goksen Kuran Aslan

Context and Objectives: Respiratory muscle training (RMT) is considered an effective tool to improve cardiorespiratory limitations in athletes. The goals of this systematic review were to explore the role of RMT and its implementation within sport rehabilitation programs in para-athletes. Evidence Acquisition: Several databases were searched until January 2024. Eligible studies were independently reviewed by 2 reviewers. Quality assessment was made using the PEDro scale and version 2 of the Cochrane Risk-of-Bias Tool for Randomized Trials. Eight studies (a total of 108 participants) were selected for the analysis. Evidence Synthesis: Five studies preferred using resistive loading, while 2 studies used normocapnic hyperpnea, and 1 study used threshold inspiratory muscle training. Respiratory functions (respiratory muscle strength and endurance, spirometry measures) and exercise performance were assessed as the main outcomes. Significant increases in respiratory muscle strength were reported in 5 studies. Two studies observed improvement in respiratory muscle endurance and 3 studies reported increased exercise capacity. Conclusions: This review suggests that although RMT can enhance respiratory muscle strength and endurance, it should not be considered the primary method for boosting the exercise performance of para-athletes. Additional research is necessary to explore the impact of various RMT techniques on different outcomes from the perspective of sport rehabilitation in para-athletes.

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The Anabolic Response to Protein Ingestion During Recovery From Exercise Has No Upper Limit in Magnitude and Duration In Vivo in Humans: A Commentary

Oliver C. Witard and Samuel Mettler

A comprehensive recent study by Trommelen et al. demonstrated that muscle tissue exhibits a greater capacity to incorporate exogenous exogenous protein-derived amino acids into bound muscle protein than was previously appreciated, at least when measured in “anabolically sensitive,” recreationally active (but not resistance-trained), young men following resistance exercise. Moreover, this study demonstrated that the duration of the postprandial period is modulated by the dose of ingested protein contained within a meal, that is, the postexercise muscle protein synthesis response to protein ingestion was more prolonged in 100PRO than 25PRO. Both observations represent important scientific advances in the field of protein metabolism. However, we respectfully caution that the practical implications of these findings may have been misinterpreted, at least in terms of dismissing the concept of protein meal distribution as an important factor in optimizing muscle tissue anabolism and/or metabolic health. Moreover, based on emerging evidence, this idea that the anabolic response to protein ingestion has no upper limit does not appear to translate to resistance-trained young women.

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Physical Fitness as a Predictor of Disability Retirement: A 9-Year Register Linked Follow-Up Study

Markus Kuusela, Valtteri Pohjola, Katariina Sarttila, Matti Munukka, Riikka Holopainen, Mikko Laaksonen, Annamari Lundqvist, and Jouni Lahti

Background: To prospectively examine the association between physical fitness and risk of disability retirement in a large population-based cohort. Methods: This study utilized data from Health 2011 survey Physical Activity subsample (n = 4898), combined with information on disability retirement derived from 2 national registers. In total, 2455 individuals aged 18–74 years underwent the physical fitness test protocol concerning measures of cardiorespiratory fitness, muscle strength, and balance. The outcome variable was disability retirement, during the follow-up period of 9 years. After excluding those not at risk of disability retirement (ie, age ≥63 y) or who had already been granted disability pension, and those who had not completed the fitness protocol, the analytical sample included 1381 participants. Data were analyzed using Cox regression model with SPSS (version 29). Results: During the 9-year follow-up period, 61 individuals (4.4%) transitioned to a disability retirement. Cox regression analysis showed an association between the various physical fitness subdomains and the risk of disability retirement. In model 1, all fitness tests were associated with the risk of disability retirement, except the one-leg stand test with hazard ratios ranging from 1.69 (95% CI, 0.86–3.34) to 5.75 (95% CI, 1.84–17.90). Further adjustment for sociodemographic, health behavior, and health-related covariates attenuated the associations and statistical significance was lost, except for the vertical jump test (hazard ratio = 4.33; 95% CI, 1.32–14.10) and 6-minute walk test (hazard ratio = 3.81; 95% CI, 1.35–10.70). Conclusion: These findings highlight the importance of physical fitness for preventing work disability.

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Protein Intake Distribution: Beneficial, Detrimental, or Inconsequential for Muscle Anabolism? Response to Witard & Mettler

Jorn Trommelen, Andrew M. Holwerda, and Luc J.C. van Loon

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Erratum. Analyzing Dual-Task Paradigms to Improve Postconcussion Assessment and Management

Journal of Sport Rehabilitation