Search Results

The effects of footwear and inclination on running biomechanics over short intervals are well documented. Although recognized that exercise duration can impact running biomechanics, it remains unclear how biomechanics change over time when running in minimalist shoes and on slopes. Our aims were to describe these biomechanical changes during a 50-minute run and compare them to those observed in standard shoes. Thirteen trained recreational male runners ran 50 minutes at 65% of their maximal aerobic velocity on a treadmill, once in minimalist shoes and once in standard shoes, 1 week apart in a random order. The 50-minute trial was divided into 5-minute segments of running at 0%, +5%, and –5% of treadmill incline sequentially. Data were collected using photocells, high-speed video cameras, and plantar-pressure insoles. At 0% incline, runners exhibited reduced leg stiffness and plantar flexion angles at foot strike and lower plantar pressure at the forefoot and toes in minimalist shoes from minute 34 of the protocol onward. However, only reduced plantar pressure at the toes was observed in standard shoes. Overall, similar biomechanical changes with increased exercise time were observed on the uphill and downhill inclines. The results might be due to the unfamiliarity of subjects to running in minimalist shoes.

Purpose: The subjective Volodalen® score (V®score) and the objective duty factor metric can both assess global running patterns. The authors aimed to investigate the relation between running economy (RE) at endurance running speeds and the global running pattern quantified using both subjective and objective measures. Methods: RE and 3-dimensional whole-body kinematics were acquired by indirect calorimetry and an optoelectronic system, respectively, for 52 trained runners during treadmill runs at 10, 12, and 14 km/h. Results: Correlations between RE and V®score and RE and duty factor were negligible and nonsignificant across speeds tested (P ≥ .20), except for a low and significant correlation between RE and V®score at 10 km/h. Conclusions: These findings suggest there is no global running pattern more economic than another at endurance running speeds. Therefore, there is no advantage of choosing, favoring, or prescribing one specific global running pattern along a continuum based on V®score or duty factor metrics, and coaches should not try to modify the spontaneous running pattern of runners at endurance running speed to improve RE.

Objective: Current return-to-sport decisions are primarily based on elapsed time since surgery or injury and strength measures. Given data that show rates of successful return to competitive sport at around 55%, there is strong rationale for adopting tools that will better inform return to sport decisions. The authors’ objective was to assess reactive strength as a metric for informing return-to-sport decisions. Design: Case-control design. Methods: Fifteen elite athletes from national sports teams (23 [6.0] y) in the final phase of their return-to-sport protocol following a unilateral knee injury and 16 age-matched control athletes (22 [4.6] y) performed a unilateral isometric strength test and 24-cm drop jump test. Pairwise comparisons were used to determine differences between legs within groups and differences in interleg asymmetry between groups. Results: Strength measures did not distinguish the control from the rehabilitation group; however, clear differences in the degree of asymmetry were apparent between the control and rehabilitation groups for contact time (Cohen d = 0.56; −0.14 to 1.27; 8.2%; P = .113), flight time (d = 1.10; 0.44 to 1.76; 16.0%; P = .002), and reactive strength index (d = 1.27; 0.50 to 2.04; 22.4%; P = .002). Conclusion: Reactive strength data provide insight into functional deficits that persist into the final phase of a return-to-sport protocol. The authors’ findings support the use of dynamic assessment tools to inform return-to-sport decisions to limit potential for reinjury.

Context: Sensorimotor training is commonly used in a rehabilitative setting; however, the effectiveness of an unexpected disturbance program (UDP) to enhance performance measures in uninjured elite athletes is unknown. Objective: To assess the impact of a 3-wk UDP program on strength, power, and proprioceptive measures. Design: Matched-group, pre-post design. Setting: National sport institute. Participants: 21 international-level female field hockey athletes. Intervention: Two 45-min UDP sessions were incorporated into each week of a 3-wk training program (total 6 sessions). Main Outcome Measures: 1-repetition-maximum strength, lower-limb power, 20-m running speed, and proprioception tests were performed before and after the experimental period. Results: Substantial improvements in running sprint speed at 5-m (4.4 ± 2.6%; effect size [ES]: 0.88), 10-m (2.1 ± 1.9%; ES: 0.51), and 20-m (1.0 ± 1.6%; ES: 0.23) were observed in the UDP group. Squat-jump performance was also clearly enhanced when compared to the control group (3.1 ± 6.1%; ES: 0.23). Small but clear improvements in maximal strength were observed in both groups. Conclusions: A 3-wk UDP can elicit clear enhancements in running sprint speed and concentric-only jump performance. These improvements are suggestive of enhanced explosive strength and are particularly notable given the elite training status of the cohort and relatively short duration of the intervention. Thus, the authors would reiterate the statement by Gruber et al (2004) that sensorimotor training is a “highly efficient” modality for improving explosive strength.

Purpose: To investigate differences in athletes’ knowledge, beliefs, and training practices during COVID-19 lockdowns with reference to sport classification and sex. This work extends an initial descriptive evaluation focusing on athlete classification. Methods: Athletes (12,526; 66% male; 142 countries) completed an online survey (May–July 2020) assessing knowledge, beliefs, and practices toward training. Sports were classified as team sports (45%), endurance (20%), power/technical (10%), combat (9%), aquatic (6%), recreational (4%), racquet (3%), precision (2%), parasports (1%), and others (1%). Further analysis by sex was performed. Results: During lockdown, athletes practiced body-weight-based exercises routinely (67% females and 64% males), ranging from 50% (precision) to 78% (parasports). More sport-specific technical skills were performed in combat, parasports, and precision (∼50%) than other sports (∼35%). Most athletes (range: 50% [parasports] to 75% [endurance]) performed cardiorespiratory training (trivial sex differences). Compared to prelockdown, perceived training intensity was reduced by 29% to 41%, depending on sport (largest decline: ∼38% in team sports, unaffected by sex). Some athletes (range: 7%–49%) maintained their training intensity for strength, endurance, speed, plyometric, change-of-direction, and technical training. Athletes who previously trained ≥5 sessions per week reduced their volume (range: 18%–28%) during lockdown. The proportion of athletes (81%) training ≥60 min/session reduced by 31% to 43% during lockdown. Males and females had comparable moderate levels of training knowledge (56% vs 58%) and beliefs/attitudes (54% vs 56%). Conclusions: Changes in athletes’ training practices were sport-specific, with few or no sex differences. Team-based sports were generally more susceptible to changes than individual sports. Policy makers should provide athletes with specific training arrangements and educational resources to facilitate remote and/or home-based training during lockdown-type events.