The impact of arm-crank position on the drag of a paralympic hand-cyclist

Aerodynamic influence of an alpine skier’s arms

Understanding how postural changes in alpine skiing affect the overall aerodynamic drag is highly important for enhancing performance. Although the arm configuration of the athlete can have a significant impact on the overall drag force, this effect is currently less understood. The purpose of this investigation was to examine how the arms of an alpine skier influence the overall drag. Experiments were performed in a wind tunnel for a male and female athlete, and computational fluid dynamics simulations were performed on 3D scans of the athletes. The influence of the arm configurations in three different scenarios are considered; low-tucked, high-tucked, and flight postures. Consistent trends are found for both athletes and between the experiments and simulations. In general, the arms were found to be highly influential of the overall drag, and hence also performance in alpine skiing. For the low-tucked posture, the maximum variation in total drag area depending upon the angle of the underarms is 2.8%, with the lowest drag found with a medium angle of 20$$^\circ $$ ∘ to 25$$^\circ $$ ∘ . For the high-tuck posture, the difference in drag area between a closed and open posture was found to be 17% to 21%. The flight postures showed the highest influence of arm configurations, with a maximum difference in drag area of 64% between the considered postures. These results contribute to the understanding of aerodynamics in alpine skiing, and could be implemented directly in the training of athletes to improve their aerodynamic performance.

The relation between sprint power and road time trial performance in elite para-cyclists

OBJECTIVES

Whilst cycling performance has been studied extensively, very little is known about the performance of para-cyclists. This study assessed the relation between sprint power and road time trial performance in elite para-cyclists, and whether this relation differed based on impairment type and type of bike used.

DESIGN

Cross-sectional.

METHODS

During international para-cycling events, 168 athletes (88 bicycles, 17 tricycles, 56 recumbent handbikes and 7 kneeling handbikes) performed 20-s sport-specific sprint tests (mean power output (POmean) W), and their road time trial performance (average speed (km/h)) was taken from the official results. Multilevel regression models to assess the relation of sprint with time trial performance were composed for i. leg-cyclists: bicycle and tricycle and ii. arm-cyclists: recumbent- and kneeling handbike, adjusted for identified confounders. Furthermore, impairment type (categorized as i) muscle power/range of motion, ii) limb deficiency/leg length difference, and iii) coordination) and bike type were tested as effect modifiers.

RESULTS

POmean ranged from 303 ± 12 W for recumbent handcyclists to 482 ± 156 W for bicyclists. POmean was significantly related to time trial performance, for both leg-cyclists (β = 0.010, SE = 0.003, p < 0.01) and arm-cyclists (β = 0.029; SE = 0.005, p < 0.01), and impairment type and bike type were not found to be effect modifiers.

CONCLUSIONS

Sprint power was related to road time trial performance in all para-cyclists, with no differences found in this relation based on impairment type nor bike type. For those competing on a bicycle, tricycle, recumbent- or kneeling handbike, sprint tests might therefore be useful to predict or monitor time trial performance.

The Relationship Between Absolute and Relative Upper-Body Strength and Handcycling Performance Capabilities

PURPOSE

To explore the relationship between absolute and relative upper-body strength and selected measures of handcycling performance.

METHODS

A total of 13 trained H3/H4-classified male handcyclists (mean [SD] age 37 [11] y; body mass 76.6 [10.1] kg; peak oxygen consumption 2.8 [0.6] L·min-1; relative peak oxygen consumption 36.5 [10] mL·kg·min-1) performed a prone bench-pull and bench-press 1-repetition-maximum strength assessment, a 15-km individual time trial, a graded exercise test, and a 15-second all-out sprint test. Relationships between all variables were assessed using Pearson correlation coefficient.

RESULTS

Absolute strength measures displayed a large correlation with gross mechanical efficiency and maximum anaerobic power output (P = .05). However, only a small to moderate relationship was identified with all other measures. In contrast, relative strength measures demonstrated large to very large correlations with gross mechanical efficiency, 15-km time-trial velocity, maximum anaerobic power output, peak aerobic power output, power at a fixed blood lactate concentration of 4 mmol·L-1, and peak oxygen consumption (P = .05).

CONCLUSION

Relative upper-body strength demonstrates a significant relationship with time-trial velocity and several handcycling performance measures. Relative strength is the product of one's ability to generate maximal forces relative to body mass. Therefore, the development of one's absolute strength combined with a reduction in body mass may influence real-world handcycling race performance.

The Anthropometric, Physiological, and Strength-Related Determinants of Handcycling 15-km Time-Trial Performance

PURPOSE

The aim of this study was to investigate the relationship between selected anthropometric, physiological, and upper-body strength measures and 15-km handcycling time-trial (TT) performance.

METHODS

Thirteen trained H3/H4 male handcyclists performed a 15-km TT, graded exercise test, 15-second all-out sprint, and 1-repetition-maximum assessment of bench press and prone bench pull strength. Relationship between all variables was assessed using a Pearson correlation coefficient matrix with mean TT velocity representing the principal performance outcome.

RESULTS

Power at a fixed blood lactate concentration of 4 mmol·L-1 (r = .927; P < .01) showed an extremely large correlation with TT performance, whereas relative V˙O2peak (peak oxygen uptake) (r = .879; P < .01), power-to-mass ratio (r = .879; P < .01), peak aerobic power (r = .851; P < .01), gross mechanical efficiency (r = 733; P < .01), relative prone bench pull strength (r = .770; P = .03) relative bench press strength (r = .703; P = .11), and maximum anaerobic power (r = .678; P = .15) all demonstrated a very large correlation with performance outcomes.

CONCLUSION

Findings of this study indicate that power at a fixed blood lactate concentration of 4 mmol·L-1, relative V˙O2peak, power-to-mass ratio, peak aerobic power, gross mechanical efficiency, relative upper-body strength, and maximum anaerobic power are all significant determinants of 15-km TT performance in H3/H4 handcyclists.

Crank length alters kinematics and kinetics, yet not the economy of recumbent handcyclists at constant handgrip speeds

Handcycling performance is dependent on the physiological economy of the athlete; however, handbike configuration and the biomechanical interaction between the two are also vital. The purpose of this study was to examine the effect of crank length manipulations on physiological and biomechanical aspects of recumbent handcycling performance in highly trained recumbent handcyclists at a constant linear handgrip speed and sport-specific intensity. Nine competitive handcyclists completed a 3-minute trial in an adjustable recumbent handbike in four crank length settings (150, 160, 170 & 180 mm) at 70% peak power output. Handgrip speed was controlled (1.6 m·s^-1 ) across trials with cadences ranging from 102 to 85 rpm. Physiological economy, heart rate, and ratings of perceived exertion were monitored in all trials. Handcycling kinetics were quantified using an SRM (Schoberer Rad Messtechnik) powermeter, and upper limb kinematics were determined using a 10-camera VICON motion capture system. Physiological responses were not significantly affected by crank length. However, greater torque was generated (P < .0005) and peak torque occurred earlier during the push and pull phase (P ≤ .001) in longer cranks. Statistical parametric mapping revealed that the timing and orientation of shoulder flexion, shoulder abduction, and elbow extension were significantly altered in different crank lengths. Despite the biomechanical adaptations, these findings suggest that at constant handgrip speeds (and varying cadence) highly trained handcyclists may select crank lengths between 150 and 180 mm without affecting their physiological performance. Until further research, factors such as anthropometrics, comfort, and self-selected cadence should be used to facilitate crank length selection in recumbent handcyclists.