The effects of high-intensity interval walking training with water immersion in middle-aged and older women with light knee osteoarthritis

 

Shuichi Handa^1,2, Yoshi-ichiro Kamijo¹, Toshiaki Yamazaki^1,3, Hirokazu Gen-no^3,4, and Hiroshi Nose^1,4

¹Department of Sports Medical Sciences, Shinshu University Graduate School of Medicine, Matsumoto 390-8621, Japan; ²Mimaki Spa Clinic, Tomi 389-0402, Japan; ³Kissei Comtec Co., Ltd., Matsumoto 390-1293; ⁴Jukunen Taiiku Daigaku Research Center, Matsumoto 390-8621, Japan

 

We examined whether high-intensity interval walking training with water immersion (IWT_W) increased the thigh strength in middle-aged older subjects with light knee osteoarthritis more than that on land (IWT_L). Thirty seven women were divided into IWT_L (n = 18, 58±6 yr) and IWT_W (n=19, 59±5 yr). In IWT_L, subjects repeated ~5 sets of 3-min slow walking at 40%VO_2peak for walking on land followed by a 3-min fast walking at ≥70%VO_2peak per day, for ~3 days/wk, for 3 mos. On the other hand, subjects in IWT_W were able to walk at higher intensity of both slow and fast walking, at 70% and ≥100%VO_2peak for walking on land, respectively, ~4 days/wk, leading to accomplish the same fast walking time as IWT_L in 2 mos. As a result, isometric knee extension and flexion forces increased by 19% and 10%, respectively, in IWT_W (both, P<0.01) while not in IWT_L. In another acute study on 19 middle-aged and older women (59±5 yr), we found that respiratory quotient and heart rate at the fastest walking were 17% and 7% 10bpm lower (both, P<0.01) while ventilation threshold was 14% higher (P<0.05) during graded walking with water immersion than that on land.  Thus, IWT_W increased the thigh muscle strength more than IWT_L by enabling subjects to perform higher intensity of walking training more frequently.

 

Key words: walking training in water, osteoarthritis, thigh muscle strength