Purpose: Anecdotally, athletic training clinicians often have patients "warm up" on a stationary cycle prior to rehabilitation. No previous studies have evaluated the rate or magnitude of muscle temperature increase during a cycling task. Our objective was to determine the rate and magnitude of muscle temperature increase in superficial (2cm) and deep (4cm) muscle during cycling at various intensities. Methods: Randomized, counter-balanced crossover trial conducted at a University research laboratory. Sixteen healthy participants (male=7, female=9; mean age 26±4 years; height 170±10 cm; weight 77±8 kg; adipose thickness 1.4±0.9 cm; muscle thickness 5.1±0.7 cm). Participants performed cycling under 3 intensity conditions: 50-80 Watts/gear 8-10 (light), 100-130 Watts/12-16 gear (moderate), 140+ Watts/16+ gear (strenuous). Main outcomes measured were muscle temperature at depths of 2cm and 4cm were measured via 17-gauge catheter thermocouple. Temperatures were recorded at baseline and during the 20-minute cycling task. Results: 2cm depth: moderate heating achieved; nonsignificant intensity-by-time interaction (F(20,80)=1.225, p=0.257, observed power 0.877). Significant main effect for time (F(20,80)=18.995, p<.001), nonsignificant main effect for intensity (F(1,4)=4.435, p=0.103, observed power 0.365). 4cm depth: moderate heating achieved; nonsignificant intensity-by-time interaction (F(20,100)=0.784, p=0.257, observed power 0.720). Significant main effect for time (F(20,100)=62.102, p<.001), nonsignificant main effect for intensity (F(1,5)=1.267, p=0.311, observed power 0.152). Conclusions: No cycling intensities were able to increase muscle temperature to the vigorous heating range (4°C increase) at either 2cm or 4cm depth. Moderate to high-intensity cycling warmup may increase local metabolic rate, decrease pain, and decrease muscle spasm via 1-2°C increase in muscle temperature.
Ostrowski J, Scifers J. Rate and Magnitude of Muscle Temperature Increase with Cycling at Various Intensities. The Internet Journal of Allied Health Sciences and Practice. 2023 Jun 29;21(3), Article 7.