Menthol-induced Cutaneous Stimulation Combined with Self-paced Walking Training Improves Knee Extension Performance in Untrained Older Healthy Females

[Purpose] The present study aimed to investigate whether self-paced walking training utilizing the facilitating effect of skin cooling with menthol gel application was effective in untrained older healthy females. [Participants and Methods] Forty-two untrained healthy older females (aged 60-69 years) were divided into the following three groups: (i) Walking training with menthol group: G, (ii) Walking training group: G, and (iii) Control group: G. The participants in G and G performed self-paced walking for 30 minutes a day, 2 times a week, for 6 weeks. Menthol gel was applied to the front of the thigh of the participants in G. Maximal voluntary contraction and rate of force development were measured pre- and post-training and walking speed was measured during the training. The number of steps taken and walking speed in daily activity were measured and the average of these parameters per day were calculated. [Results] The main findings were [1] knee extension muscle strength increased in G and G, and [2] rate of force development only improved in G. [Conclusion] These results suggest that walking training utilizing the facilitating effect of skin cooling enhances muscle function in untrained older healthy females and that the present skin cooling method with menthol gel application may be recommended as a training strategy.