Bioenergetics and Biomechanics of Handcycling at Submaximal Speeds in Athletes with a Spinal Cord Injury

Abstract

Background: A study aimed at comparing bioenergetics and biomechanical parameters between athletes with tetraplegia and paraplegia riding race handbikes at submaximal speeds in ecological conditions.

Methods: Five athletes with tetraplegia (C6-T1, 43 ± 6 yrs, 63 ± 14 kg) and 12 athletes with paraplegia (T4-S5, 44 ± 7 yrs, 72 ± 12 kg) rode their handbikes at submaximal speeds under metabolic measurements. A deceleration method (coasting down) was applied to calculate the rolling resistance and frontal picture of each participant was taken to calculate air resistance. The net overall Mechanical Efficiency (Eff) was calculated by dividing external mechanical work to the corresponding Metabolic Power.

Results: Athletes with tetraplegia reached a lower aerobic speed (4.7 ± 0.6 m s^-1 vs. 7.1 ± 0.9 m s^-1, P = 0.001) and Mechanical Power (54 ± 15 W vs. 111 ± 25 W, P = 0.001) compared with athletes with paraplegia. The metabolic cost was around 1 J kg^-1 m^-1 for both groups. The Eff values (17 ± 2% vs. 19 ± 3%, P = 0.262) suggested that the handbike is an efficient assisted locomotion device.

Conclusion: Handbikers with tetraplegia showed lower aerobic performances but a similar metabolic cost compared with handbikers with paraplegia at submaximal speeds in ecological conditions.

Keywords: handbike; locomotion; paralympic classification; paralympic sport; performance.

Figure 1

Recumbent handbike.

Figure 2

Speed (A), Metabolic Power (B), (external) Mechanical Power (C), and the (overall) Mechanical Efficiency (D) of athletes with tetraplegia and paraplegia riding race handbikes.

Figure 3

Oxygen consumption (VO₂) and metabolic cost (C) over speed in athletes with tetraplegia 165 (black circles) and paraplegia (empty circles). Exponential regression lines for graphical purposes only: through values featuring athletes with tetraplegia, VO₂ = 6.39 e0.189 speed; R² = 0.54; n = 14) and paraplegia 167 (VO₂ = 8.79 e0.149 speed; R² = 0.64; n = 39).