Browse

Purpose: To study whether, during typical-level running, non-rear-foot strikers (non-RFS) or rear-foot strikers (RFS) presented a similar or different extent of neuromuscular fatigue after a prolonged graded run. Methods: Sixteen experienced male trail runners (8 non-RFS and 8 RFS) performed a 2.5-hour treadmill graded running exercise. Before and after exercise, neuromuscular tests were performed to assess neuromuscular fatigue of the plantar flexors. Biomechanical gait parameters were acquired with an instrumented treadmill, and electromyographic activity of the lower-limb muscles was collected as an index of muscle activation. Results: There were no significant time × foot strike interactions for neuromuscular (all P ≥ .742), muscle activation (all P ≥ .157), or biomechanical (all P ≥ .096) variables. Conclusions: A dominant level running foot-strike pattern did not directly affect the extent of neuromuscular fatigue during a prolonged graded run. This suggests that no ideal running foot-strike pattern exists to minimize neuromuscular fatigue during prolonged-duration races wherein cumulative uphill and downhill segments are high, such as in trail running.

Background: Tai Chi Chuan (TCC) is considered a mind and body practice of Chinese origin, considered as an intangible cultural heritage of humanity by UNESCO, and recommended by the World Health Organization as a therapeutic approach to prevent falls. Objective: To assess the effects of TCC on older adult’s balance. Methods: A systematic review of randomized clinical trials was conducted by two independent reviewers using the ROB2 tool to assess the risk of bias under the following databases: PubMed, SCOPUS, Web of Science, PEDro, Embase, Cochrane, CINAHL, and LILACS. A meta-analysis of the selected articles for the dynamic and static balance criteria was conducted in a population of older adults (over 65 years) with publications from 2010 to 2024. Results: Eighteen randomized clinical trials fulfilled the criteria. TCC improves dynamic balance in the timed up and go and gait speeds tests, and static balance in the single-leg test and functional reach test when compared with the control group in the meta-analysis. Adverse events were found in only one study, and the training parameters were heterogeneous. Conclusion: TCC improves older adults with both dynamic and static balance. The results of the parameters indicate a direction in which TCC is prescribed for clinical practice with minimal or no risk of adverse effects.

The study analyzed the gaze behavior and decision-making performance of 20 soccer assistant referees while judging offside events. Specifically, gaze behaviors, gaze entropy, and estimated quiet eye (eQE; defined as the last fixation prior to the attacker’s ball pass) characteristics (i.e., location, onset, offset, and duration) were analyzed in relation to decision-making accuracy. Although a significant number of fixations were observed on the offside line, the highest viewing time corresponded to the ball carrier. The gaze behavior indicated a high distribution of fixations, as evidenced by high stationary gaze entropy (>90%). The assistant referees also distinguished offside from onside positions above chance. However, they displayed nonprolonged eQE on the offside line. As a result, no significant relationships were found between the eQE characteristics and decision-making accuracy. The study concludes that the absence of more functional gaze behaviors, specifically with longer eQE focused on the offside line, impaired the decision-making accuracy of nonexpert assistant referees in soccer.

Quiet eye (QE), the visual fixation on a target before initiation of a critical action, is associated with improved performance. While QE is trainable, it is unclear whether QE can directly predict performance, which has implications for training interventions. This study predicted basketball shot outcome (make or miss) from visuomotor control variables using a decision tree classification approach. Twelve basketball athletes completed 200 shots from six on-court locations while wearing mobile eye-tracking glasses. Training and testing data sets were used for modeling eight predictors (shot location, arm extension time, and absolute and relative QE onset, offset, and duration) via standard and conditional inference decision trees and random forests. On average, the trees predicted over 66% of makes and over 50% of misses. The main predictor, relative QE duration, indicated success for durations over 18.4% (range: 14.5%–22.0%). Training to prolong QE duration beyond 18% may enhance shot success.

Purpose: Rigorous evidence concerning the reliability of physical tests among young athletes is lacking. Therefore, this study aimed to comprehensively determine the retest reliability of the most commonly used tests to assess physical qualities in adolescent rugby league players, and to provide the standard error of measurement and minimal detectable change for each test to support objective athlete monitoring. Method: A repeated-measures design was employed with 50 adolescent, schoolboy rugby league players (16.2 [1.3] y) completing the same testing battery across 2 consecutive weeks. Within each week, stature, body mass, and ∑4 skinfold thickness assessments, as well as countermovement jump, medicine ball throw, and 1-repetition maximum bench press, back squat, and prone row tests were conducted on the first testing day. Forty-eight hours later, a second testing day contained the 10- and 20-m linear sprints, 505-Agility Test, L-run Test, and Multistage Fitness Test. Results: Nonsignificant (P > .05), trivial differences (d _av = 0.00–0.16) were evident between trials in all tests. The coefficient of variation ranged from 0.05% to 4.02% across tests. The intraclass correlation ranged from .704 to .999. All tests presented relatively low standard error of measurement, with accompanying minimal detectable change provided. Conclusion: These data can help inform decision making among end-users when implementing tests in a repeated manner and interpreting testing data.

Purpose: To examine the reproducibility and sensitivity of a self-paced field running test (SFT) in monitoring positive and negative changes in endurance performance. Methods: A total of 27 (11 women) recreational runners participated in a 6-week training intervention. The intervention was divided into a 3-week baseline period, a 2-week overload period, and a 1-week recovery period. An incremental treadmill test was performed before the baseline period and a 3000-m running test before and after all periods (T1–T4). In addition, the participants performed once a week an SFT (SFT1–6), which consisted of submaximal (6 + 6 + 3-min test at perceived exertion of 9/20, 13/20, and 17/20) and maximal sections (6 × 3-min intervals at maximum sustainable effort). The associations between the incremental treadmill test and the SFT1 performance were examined with the Pearson correlation, and the intraclass correlation was analyzed for the parameters of SFT1 to SFT3 sessions during the baseline period. The repeated-measures correlation was calculated for the 3000-m speed at T1 to T4 and the corresponding speeds at SFT. Results: Significant associations (r = .68–.93; P < .001) were found between the speeds of the SFT and the peak and lactate threshold speeds of the incremental treadmill test. Intraclass correlations varied between .77 and .96, being the highest for the average speed of 6 × 3-minute intervals. Repeated-measures correlation was significant (P < .05) for the 9/20 (r = .24), 13/20 (r = .24), and 6 × 3-minute intervals (r = .29). Conclusions: The SFT seemed a reproducible method to estimate endurance performance in recreational runners. The sensitivity to track short-term and small-magnitude changes in performance seems more limited and might require more standardized conditions.

Background: Exercise optimizes peak bone mass accrual, particularly if the loading is high magnitude and distributed in abnormal directions. Little is known about the influence of early intense training in sport during peak bone mass accrual, especially in boys. Methods: Ninety-eight males aged 6–24 years (gymnasts, swimmers, and controls) completed the bone-specific physical activity questionnaire and a 7-day exercise diary. Dual-energy X-ray absorptiometry determined bone mineral properties of the total body (less head) and lumbar spine (LS, L1–L4) and total lean mass. Subgroup analyses were conducted for juniors (prepubescent), adolescents (11–16 y), and seniors (17–24 y). Results: Lean mass was positively associated with total body less head and LS bone outcomes in all 3 age groups (R ² = .632–.770, P < .05), and bone-specific physical activity questionnaire scores were associated with LS bone mineral density in adolescents and seniors (R ² = .440 and .591, P < .05). Senior gymnasts had significantly higher LS bone mineral density (in grams per square centimeter) and Z-scores than swimmers (P = .004) and controls (P = .012). Conclusions: Elite gymnastics is associated with superior peak bone mass accrual in young males. The benefits appear more pronounced during young adulthood compared with prepuberty, potentially reflecting an extended time course for bone adaptation.

Purpose: To investigate the effect of a newly developed hand rim in wheelchair tennis players from a lab and field perspective. Methods: Nine wheelchair tennis players performed a set of field and lab tests with the new rim (NR) and regular rim on the racket side. Each player had a 60- to 120-minute regular training session with the NR. Three wheelchair tennis field tests (20-m sprint, Illinois, spider) were completed on a hard court using inertial measurement units. The inertial measurement units enabled analysis of linear/rotational velocity and acceleration. In the lab, two 4-minute submaximal tests (at 1.5 and 2 m/s, 0.2 W/kg), followed directly by a 5-second sprint, on a wheelchair ergometer were completed. Force and velocity were measured continuously throughout all tests. Mixed linear models investigated the effect between the 2 hand rims. Results: During the spider test, mean rotational velocity to the racket side (−2%, P = .005) was lower in the NR, and end times were similar between hand-rim conditions. No differences were observed in the 20-m sprint and Illinois field tests. In the lab, contact angle (+6%, P = .04), cycle time (+12%, P = .007), and work per push (+13%, P = .005) were higher in the NR during submaximal propulsion. Work per push (+13%, P = .007), peak velocity (+3%, P < .001), and distance covered (+4%, P = .02) were higher with the NR during the 5-second sprint test. Conclusions: The NR seems slightly favorable compared with the regular rim during performance testing on a wheelchair ergometer in wheelchair tennis players. A longer practice time might show more insights between the hand-rim types.