Force-velocity profiling of elite wheelchair rugby players by manipulating rolling resistance over multiple wheelchair sprints.

This study investigated the effect of increased rolling resistance on wheelchair sprint performance and the concomitant force-velocity characteristics. Thirteen wheelchair rugby (WCR) athletes completed five 15 s wheelchair sprints in their own rugby wheelchair on an instrumented dual-roller wheelchair ergometer. The first sprint was performed against a close to overground resistance and in each of the following sprints, the resistance increased with 80% of that resistance. A repeated-measures ANOVA examined differences between sprints. Subsequently, linear regression analyses examined the individual force-velocity relations and then, individual parabolic power output curves were modeled. Increased rolling resistance led to significantly lower velocities (-36%), higher propulsion forces (+150%) and higher power outputs (+83%). These differences were accompanied by a lower push frequency, higher push time, yet a constant recovery time and contact angle. The modeled linear regressions (R2 = 0.71 ± 0.10) between force and velocity differed a lot in slope and intercept among individual athletes. The peak of the power output parabola (i.e., the optimal velocity) occurred on average at 3.1 ± 0.6 ms-1 . These individual force-velocity profiles can be used for training recommendations or technological changes to better exploit power generation capabilities of the WCR athletes' musculoskeletal system.

Toward a Standardized and Individualized Laboratory-Based Protocol for Wheelchair-Specific Exercise Capacity Testing in Wheelchair Athletes: A Scoping Review.

ABSTRACT: Previous studies on handrim wheelchair-specific (an)aerobic exercise capacity in wheelchair athletes have used a diversity of participants, equipment, and protocols. Therefore, test results are difficult to compare among studies. The first aim of this scoping review is to provide an overview of the populations studied, the equipment and protocols used, and the reported outcomes from all laboratory-based studies on wheelchair-specific exercise capacity in wheelchair athletes. The second aim is to synthesize these findings into a standardized, yet individualized protocol. A scoping literature search resulted in 10 anaerobic and 38 aerobic protocols. A large variety in equipment, protocol design, and reported outcomes was found. Studies that systematically investigated the influence of protocol features are lacking, which makes it difficult to interpret and compare test outcomes among the heterogeneous group of wheelchair athletes. Protocol design was often dependent on a priori participant knowledge. However, specific guidelines for individualization were missing. However, the common protocol features of the different studies were united into guidelines that could be followed when performing standardized and individualized wheelchair-specific exercise capacity tests in wheelchair athletes. Together with guidelines regarding reporting of participant characteristics, used equipment, and outcome measures, we hope to work toward more international agreement in future testing.

Evaluation of a standardized test protocol to measure wheelchair-specific anaerobic and aerobic exercise capacity in healthy novices on an instrumented roller ergometer.

This study aims to evaluate whether a test protocol with standardized and individualized resistance settings leads to valid wheelchair Wingate tests (WAnT) and graded exercise tests (GXT) in healthy novices. Twenty able-bodied individuals (10M/10F, age 23 ± 2 years, body mass 72 ± 11 kg) performed an isometric strength test, sprint test, WAnT and GXT on a wheelchair ergometer. Using a previously developed set of regression equations, individuals' isometric strength outcome was used to estimate the WAnT result (P30est), from which an effective individual WAnT resistance was derived. The subsequently measured WAnT outcome (P30meas) was used to estimate the GXT outcome (POpeakest) and to scale the individual GXT resistance steps. Estimated and measured outcomes were compared. The WAnT protocol was considered valid when maximal velocity did not exceed 3 m·s-1; the GXT protocol was considered valid when test duration was 8-12 min. P30est did not significantly differ from P30meas, while one participant did not have a valid WanT, as maximal velocity exceeded 3 m·s-1. POpeakest was 10% higher than POpeakmeas, and six participants did not reach a valid GXT: five participants had a test duration under 8 min and one participant over 12 min. The isometric strength test can be used to individually scale the WAnT protocol. The WAnT outcome scaled the protocol for the GXT less accurately, resulting in mostly shorter-than-desired test durations. In conclusion, the evaluated standardized and individualized test protocol was valid for the WAnT but less valid for the GXT among a group of novices. Before implementing the standardized individual test protocol on a broader scale, e.g. among paralympic athletes, it should be evaluated among different athletic wheelchair-dependent populations.

Giant Slalom: Analysis of Course Setting, Steepness and Performance of Different Age Groups - A Pilot Study.

Introduction: Giant slalom is the core discipline of alpine skiing, and each race has its own specific course and terrain characteristics. These variations may explain differences in the speed and time per turn profiles, which are essential for performance development and injury prevention. This study aims to address the differences in course setting and steepness of the different course sections (flat-medium-steep) and compare them to the performance parameters among young (U12, U14, U16) and older (U18, U21, elite) male athletes. Methods: The study examined a total sample size of 57 male athletes; 7 from elite level, 11 from U21, 13 from U18, 6 from U16, 13 from U14, and 7 from U12. The athletes wore a portable global navigation satellite system (GNSS) sensor to extract performance parameters. The course profiles and gate positions of nine runs were measured with differential GNSS. The runs were divided into flat, medium and steep sections. From the performance parameters (speed, time per turn, etc.) and the course setting variables, the mean value per section was calculated and used for the further analysis. Results: In total, 192 run sections from 88 runs were recorded and analyzed. Comparisons between course settings in young and older classes showed no significant differences. However, the turning angles and horizontal gate distances were smaller in flat sections. Average speed (49.77 vs. 65.33 km/h) and time per turn (1.74 vs. 1.41 s) differed significantly between young and U21/elite categories. In medium terrain sections U21 and elite athletes spent more time in the gliding phase compared to all other athletes. Discussion: It seems to be a reasonable that, given similar course setting and steepness, speed increases concurrently with the technical and tactical skills of the athlete. Moreover, the finding that the elite athletes spent more time in the gliding phase could be crucial for understanding technique and performance development in young athletes.