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The decision of the Union Internationale de Pentathlon Moderne to replace horse riding with Obstacle after the 2024 Olympic Games challenges training, testing, and recovery management in Modern Pentathlon. This commentary discusses physiological, technical, and tactical effects of rule changes in the 5 disciplines with a specific focus on the new discipline Obstacle. Modern Pentathlon requires athletes to develop specific endurance capacities relying on both the aerobic and anaerobic systems while simultaneously increasing lower- and upper-body strength capabilities. In addition, movements must be repeatedly executed in an explosive and precise manner. Running and swimming must be fast but economical. Swapping from horse riding to Obstacle will prioritize the explosive strength of the upper extremities and core while keeping high levels of endurance and precision in swimming, fencing, and shooting. Moreover, condensing the Modern Pentathlon competition to a 90-minute television-friendly format enables more competitions in the future. Athletes and coaches will thus also need to develop and maintain effective individual peri-exercise routines (before, during, and after the competition) to successfully meet the resulting tactical and physical challenges of the new format. This commentary aims to stimulate the discussion on the effect of the Union Internationale de Pentathlon Moderne’s decisions to replace riding with the new Obstacle discipline and implement a more television-friendly format with a focus on physiological, technical, and tactical aspects.

Objective: Micronutrient status, specifically vitamin D and iron, represent modifiable factors for optimizing military readiness. The primary purpose of this investigation was to determine associations between micronutrient deficiency (i.e., iron status and 25-hydroxy-vitamin D [25(OH)D]) and operationally relevant outcomes (i.e., skeletal health, musculoskeletal injury) at baseline and post-10 weeks of arduous military training. Methods: A total of 227 (177 men, 50 women) Marine Officer Candidates School (OCS) candidates who completed OCS training with complete data sets were included in this analysis. Vitamin D and iron status indicators were collected at two timepoints, pre (baseline) and post OCS. Musculoskeletal outcomes at the mid- and proximal tibial diaphysis were assessed via peripheral quantitative computed tomography. Results: Micronutrient status declined following OCS training in men and women and was associated with musculoskeletal outcomes including greater bone strength (strength strain index) at the mid-diaphysis site in those with optimal status (M = 38.26 mm³, SE = 15.59) versus those without (M = −8.03 mm³, SE = 17.27). In women (p = .037), endosteal circumference was greater in the deficient group (M = 53.26 mm, SE = 1.19) compared with the optimal group (M = 49.47 mm, SE = 1.31) at the proximal diaphysis. In men, greater baseline hepcidin concentrations were associated with an increased likelihood of suffering musculoskeletal injury during training. Conclusions: Vitamin D and iron status declined over the course of training, suggesting impaired micronutrient status. Differences in musculoskeletal outcomes by micronutrient group suggests optimal vitamin D and ferritin concentrations may exert beneficial effects on bone fatigability and fracture reduction during military training.

This study aimed to investigate the effects of caffeine ingestion by chewing gum (GUM_CAF) combined with priming exercise on pulmonary oxygen uptake ( ${\dot{\mathrm{V}}\mathrm{O}}_2$ ) and near-infrared spectroscopy-derived muscle oxygen extraction (HHb + Mb) kinetics during cycling performed in a severe-intensity domain. Fifteen trained cyclists completed four visits: two under a placebo gum (GUM_PLA) and two under GUM_CAF ingestion. Each visit consisted of two square-wave cycling bouts at Δ70 intensity (70% of difference between the ${\dot{\mathrm{V}}\mathrm{O}}_2$ at first ventilatory threshold and ${\dot{\mathrm{V}}\mathrm{O}}_2\text{max}$ ) with duration of 6 min each and 5 min of passive rest between the bouts. The GUM_PLA or GUM_CAF (400 mg) was chewed for 5 min, 12 min before the first Δ70 bout in a randomized double-blind procedure. The fundamental phase and slow component of HHb + Mb and ${\dot{\mathrm{V}}\mathrm{O}}_2$ kinetics were evaluated. For HHb + Mb kinetics, regardless of ingested gum, priming exercise effects occurred on the time constant (GUM_CAF 16.0 ± 4.0 vs. 13.9 ± 2.9 s; GUM_PLA 15.7 ± 6.1 vs. 13.2 ± 2.5 s), amplitude, slow component, time delay, and mean response time parameters (p ≤ .032). For ${\dot{\mathrm{V}}\mathrm{O}}_2$ kinetics, there were significant effects of bouts on the amplitude, slow component, end ${\dot{\mathrm{V}}\mathrm{O}}_2$ , and the gain kinetics parameters (p < .017). Baseline ${\dot{\mathrm{V}}\mathrm{O}}_2$ was higher during GUM_CAF than GUM_PLA (p = .020). No significant effects occurred for the interaction between gum and bout in any parameter of ${\dot{\mathrm{V}}\mathrm{O}}_2$ or HHb + Mb kinetics. Therefore, unlike the priming exercise in severe-intensity exercise, GUM_CAF is not an effective strategy for improving ${\dot{\mathrm{V}}\mathrm{O}}_2$ or HHb + Mb kinetics acceleration.

Daily living activities present a diverse array of task and environmental constraints, highlighting the critical role of adapting gait initiation (GI) for an individual’s quality of life. This study investigated the effects of GI directions, obstacle negotiation, and leg dominance on anticipatory postural adjustments and stepping kinematics. Fourteen active, young, healthy individuals participated in GI across 4 directions—forward, medial 45°, lateral 45°, and lateral 90°—with variations in obstacle presence and leg dominance. Results revealed a consistent decreasing trend in maximum center of pressure displacement, anticipatory postural adjustment duration, step distance, and swing leg velocity with lateral shifts in GI directions, yet the step duration and swing leg heel trajectory were not affected by GI directions except in lateral 90° GI. Center of pressure displacements were intricately scaled to directional propulsive forces generation, and the stepping kinematics were influenced by the directional modifications in movements. With obstacles, modifications in anticipatory postural adjustment metrics and stepping kinematics reflected the obstacle clearance movements. The dominant leg GI exhibited longer step durations and greater movement variability in medial 45° GI. The current investigation of GI factors expands our existing understanding of GI dynamics and offers valuable insights applicable to fall prevention and gait rehabilitation strategies.

Background: Beam walking is a highly studied assessment of walking balance. Recent research has demonstrated that brief intermittent visual rotations and occlusions can increase the efficacy of beam walking practice on subsequent beam walking without visual perturbations. We sought to examine the influence of full vision removal during practice walking on a treadmill-mounted balance beam. Although visual disruptions improved performance of this task, we hypothesized that removing visual feedback completely would lead to less balance improvements than with normal vision due to the specificity of practice. Methods: Twenty healthy young adults trained to walk at a fixed speed on a treadmill-mounted balance beam for 30 min, either with, or without, normal vision. We compared their balance pre-, during, and posttraining by calculating their step-offs per minute and the percentage change in step-offs per minute. Results: Balance improved in both groups after training, with no significant difference in percentage change in step-offs between the normal vision and the no vision participants. On average, the no vision participants had twice as many step-offs per minute as the normal vision group during training. Conclusion: Although previous experiments show that intermittent visual perturbations led to large enhancements of the effectiveness of beam walking training, completely removing visual feedback did not alter training effectiveness compared with normal vision training. It is likely a result of sensory reweighting in the absence of vision, where a greater weight was placed on proprioceptive, cutaneous, and vestibular inputs.

Background: The purpose of this scoping review was to systematically synthesize barriers and facilitators for physical activity (PA) among children and youth with autism spectrum disorders (ASD) across the socioecological model. Methods: Five electronic databases were searched in March 2022 for studies examining barriers and facilitators for PA among children and youth with ASD. An updated search was performed in April 2024. The framework synthesis method was utilized, and the socioecological model was the chosen framework. Results: Fifty-four studies published from 2008 to 2024 were included. Among the included studies, 57% included the perspectives of children and youth with ASD alone or together with proxies (eg, parents, teachers, and coaches), while 43% included only the perspectives of proxies. Barriers and facilitators on the intrapersonal and interpersonal levels were most substantial. The analysis led to 2 main categories of barriers and facilitators, those unique to children and youth with ASD, and those similar to what had been identified through research on children and youth, both typically developing and with other disabilities. Conclusions: This comprehensive scoping review shows the complexity of factors contributing to barriers and facilitators for PA among children and youth with ASD, and highlights both the factors unique to this population and more general factors affecting PA participation. The findings from this synthesis might be used to guide the development of inclusive PA in physical education, organized sports, and other community PA arenas.

The mechanical efficiency of human locomotion has been studied extensively. The mechanical efficiency of the whole body occasionally exceeds muscle efficiency during bouncing type gaits. It is thought to occur due to elasticity and stiffness of the tendinomuscular system and neuromuscular functions, especially stretch reflexes. In addition, the lower limb joint kinetics affect mechanical efficiency. We investigated the impact of varying external work on mechanical efficiency and lower limb kinetics during repeated sledge jumping. Fifteen male runners performed sledge jumping for 4 minutes at 3 different sledge inclinations. Lower limb kinematics, ground reaction forces, and expired gases were analyzed. Mechanical efficiency did not differ according to sledge inclination. Mechanical efficiency correlated positively with the positive mechanical work of the knee and hip joints and the negative contribution of the hip joints. Conversely, it correlated negatively with both the positive and negative contributions of the ankle joint. This may be attributable to the greater workload in this study versus previous studies. To achieve greater external work, producing more mechanical energy at the proximal joint and transferring it to the distal joint could be an effective strategy for improving mechanical efficiency because of the greater force-generating capability of distal joint muscles.

Background: Recent statistics highlight cardiovascular diseases (CVD) as a major global cause of death. This review examines the methodological approaches and the main results of independent, stratified, and joint association of sedentary time (ST) and physical activity (PA) on CVD outcomes. Methods: We searched PubMed, Embase, Web of Science, and Scopus for prospective cohorts that examined the independent, stratified, or joint associations of ST and PA with CVD outcomes. Independent associations were defined as analyses mutually adjusted for PA and ST. Stratified associations were considered when there was a reference group in each stratum of PA or ST, and joint associations were defined by a single reference group for all other combined categories of ST and PA levels. Results: Of 45 articles, 69% explored independent association of ST or PA on CVD outcomes, while 31% using a stratified/joint approach. Most studies used self-reports for ST and PA and focused on CVD mortality. Mutually adjusted analyses identified ST positively and PA inversely associated to CVD outcomes. Stratified studies showed higher ST’s pronounced impact on CVD for lower PA levels. High PA mitigated but did not eliminate ST’s negative impact. Joint analyses revealed highest CVD risk in those with both high ST and low PA, and elevated risk in various intermediate combinations. Conclusions: Employing independent, stratified, and joint association approaches can yield distinct and complementary public health messages aimed at promoting cardiovascular health. Recommendations should aim to not only to encourage boosting PA levels, but also, concurrently decrease ST.