Criterion-related validity and reliability of the standing long jump test in adults: The Adult-Fit project

The purpose of this study was to analyze the criterion-related validity and the reliability of the standing long jump test (SLJ) for evaluating the lower-body explosive muscular strength in adults. A total of 410 adults participated in this study. Sociodemographic, anthropometric measurements, laboratory lower-body muscular strength tests, and the field-based SLJ were performed. In validity analysis, stepwise regression analysis showed that maximal horizontal power, sex, percentage of body fat, maximal horizontal force, and lean mass were significantly associated with the SLJ distance (R2 = 0.78; p < 0.001). Reliability analysis showed significant differences between test-retest in the SLJ test, with an overestimation of the second measurement compared to the first [12.14 ± 14.46 cm, intraclass correlation coefficient (ICC) = 0.94 (0.75-0.97), p < 0.001; Cohen's d = 0.31]. The coefficient of variation (CV) was 7.06% and the minimal detectable change (MDC90) was 29 cm. After a learning period, higher reliability values were found [0.45 ± 1.04 cm, ICC = 1.00 (0.99-1.00); p = 0.001; CV = 0.53 %; MDC90 = 1 cm]. The SLJ test may be a valid tool to assess lower-body explosive muscular strength in the adult population. A learning period may be necessary to provide reliability on the SLJ test.

Bioinspired Soft Electrostatic Accordion-Fold Actuators

Increasing interests have been directed toward the exploitation of origami techniques in developing biomimetic soft robots. There is a need for effective design solutions to exploit the properties of origami structure with simplified assembly and improved robotic mobility. In this study, inspired by human long-standing jumps, we present a soft electrostatically driven legged accordion fold actuator made by turning a flat paper into hollow polyhedron structure with a spring like rear and capable of electrostatic pad-assisted steering and carrying loads. Without the need for integration of external actuators, the actuator is composed of the electrostatic origami actuator itself supported by a single-fold leg with fast response, easy fabrication process, and low cost. Initiated by periodic deformation around the folding hinges caused by alternating current voltage and ground reaction forces, the actuators exhibit a unique jump-slide movement outperforming other existing soft electrostatic actuators/robots in terms of relative speed. We examined the effect of different geometric and external factors on the relative speed and highlighted the significance of body scale and short-edge panels as the elastic elements, as well as operating at resonance frequency in producing effective performances. Theoretical locomotion models and finite element analysis were carried out to interpret the working principle and validate experimental results.

What Makes Parkour Unique? A Narrative Review Across Miscellaneous Academic Fields

Parkour is a growing sport that mostly involves jumping, vaulting over obstacles, and climbing in a non-dedicated setting. The authors gathered all known relevant literature across miscellaneous academic fields in order to define parkour with regard to other sports disciplines. Parkour is a lifestyle sport, and as such provides an alternative to mainstream sports, away from strict rules, standardized settings, and necessary competitions. Traceurs (parkour adepts) consider the city as a playground and as an outlet for their creativity, but they also have a strong taste for hard and individualized challenges. They usually train on non-specific structures, at ground level. Although their social background is not clear, they are mostly young and male. Traceurs are stronger than recreational athletes, especially in eccentric exercises. However, their endurance skills may be below average. One of the core specificities of parkour is its precision constraint at landing, which turns a standing long jump into a precision jump, regulated in flight so as to prepare for landing. The running precision jump follows the same landing pattern, and its flight phase contrasts with long jump techniques. Injuries, which are not more frequent than in other sports, often occur at landing and to lower limb extremities. This risk is mitigated by targeting the landing area with the forefoot instead of letting the heel hit the ground like in gymnastics, or with rolling in order to dissipate the impact. Overall, parkour focuses on adaptability to new environments, which leads to specific techniques that have not yet been extensively addressed by the literature.

Effect of transcranial direct current stimulation on the psychomotor, cognitive, and motor performances of power athletes

In sports science, transcranial direct current stimulation (tDCS) has many unknown effects on neuromuscular, psychomotor and cognitive aspects. Particularly, its impact on power performances remains poorly investigated. Eighteen healthy young males, all trained in a jumping sport (parkour) performed three experimental sessions: anodal tDCS applied either on the left dorsolateral prefrontal cortex (dlPFC, cathode in supraorbital area) or on the primary motor cortex (M1, cathode on contralateral shoulder), and a placebo condition (SHAM), each applied for 20 min at 2 mA. Pre and post, maximal vertical and horizontal jumps were performed, associated to leg neuromuscular assessment through electromyography and peripheral nerve stimulations. Actual and imagined pointing tasks were also performed to evaluate fine motor skills, and a full battery of cognitive and psychomotor tests was administered. M1 tDCS improved jump performance accompanied by an increase in supraspinal and spinal excitabilities. dlPFC stimulation only impacted the pointing tasks. No effect on cognitive tests was found for any of the tDCS conditions. To conclude, the type of performance (maximal versus accurate) affected depended upon the tDCS montage. Finally, athletes responded well to tDCS for motor performance while results to cognitive tests seemed unaffected, at least when implemented with the present rationale.

Effects of functional movement skills on parkour speed-run performance

Parkour speed-runs require performers (known as Traceurs) to negotiate obstacles with divergent properties such as angles, inclinations, sizes, surfaces, and textures in the quickest way possible. The quicker the run, the higher the performer is ranked. Performance in Parkour speed-runs may be regulated through Parkour Traceurs' functional movement skill capacities given the physical requirements of the event. This study examined what functional movement skills correlate with Parkour speed-run performance. Nineteen male Parkour Traceurs undertook a physical testing battery inclusive of: agility T-test, maximal grip strength test, and maximal vertical and horizontal jumps across several jump modalities. For the speed-run, Parkour Traceurs navigated an indoor Parkour installation. Pearson's correlation analyses (r) revealed that agility T-test performance showed a significant positive correlation with Parkour speed-run performance, whereas standing long jump and counter movement jump (with and without arm swing) were significantly negatively correlated with Parkour speed-run performance. Concurrent with the intrinsically-linked building blocks in the Athletic Skills Model, the data from the present study suggest that performance in Parkour-speed-runs are underpinned by functional movement skills (jumping, running; arm swinging) and conditions of movement (agility), all of which encapsulate elements of basic motor properties (speed; strength). From a practical perspective, the agility T-test, standing long jump, and counter movement jump with and without arm swing can form a basic battery to evaluate the physical effects of Parkour speed-run interventions on functional movement skills.Highlights As Parkour speed-runs could be implemented to improve functional movement skills in different domains (indoors, outdoors, collectively as members of a team or individually), it was important to explore what composition of a battery of standardised athletic tests for functional movement skills correlated to Parkour speed-run performance (time to completion).In line with the intrinsically-linked building blocks in the Athletic Skills Model, the data from the present study suggest that performance in Parkour-speed-runs are underpinned by functional movement skills (jumping, running; arm swinging) and condition of movement (agility), all of which encapsulate elements of basic motor properties (speed; strength).Testing batteries examining the effects of Parkour speed-run interventions should include the following: agility T-test, CMJ jumps without arm swing using both feet and the dominant and the non-dominant foot, SLJ, and CMJ jumps with an arm swing component using both feet and the dominant and the non-dominant foot.