Elderly Oarsmen Have Larger Major Psoas Muscle Mass

Abstract

Knee extensor muscle (KE) and major psoas muscle (MP) of trunk play a decisive role in walking, stair ascent/descent, and so on in humans. Particularly, it is important for elderly people to prevent the weakness of these muscles to enhance quality of life. Rowing consists of rhythmical muscle contractions in both the lower and upper body, and demands a high aerobic capacity (Secher et al., 1983). Early study suggested that rowing prevents the wasting of leg extensor muscle in elderly men (Yoshiga et al., 2002), whereas no information is available on MP in elderly rowers. PURPOSE: For the purpose of examining the preventive effect of rowing on MP mass, in the present study, we compared MP mass and trunk flexion force in elderly male rowers with age-matched untrained men. METHODS: Participants were 22 elderly rowing trained men (RT; age: 67.5±2.5 yrs, height: 172.0±4.8 cm, body mass: 69.4±7.0 kg, Fat Free Mass (FFM): 55.9± 3.7 kg, VO2peak:37.6±6.3 mL/kg/min, mean±SD) and 19 untrained elderly men(UT:66.0±2.5 yrs, 164.7±4.2 cm, 63.4±8.1 kg, 49.7 ± 4.8 kg, 28.7 ± 5.7 mL/kg/min). Muscle cross-sectional area (CSA) was measured on MP and KE by magnetic resonance imaging, and bilateral leg extension power and trunk flexion force were measured. RESULTS: The CSAs of MP and KE in RT were significantly larger by 45% and 15% than those in UT, respectively (RT vs UT; MP: 30.2±5.2 vs 20.9±4.3 cm2, p < 0.001. KE: 120.7±15.6 vs 105.1±17.7 cm2, p < 0.01). MP CSA per FFM of RT was 29% higher than that of UT (RT: 0.54±0.09 vs UT: 0.42±0.08 cm2/kgFFM, p<0.001), while there was no significant difference between the two groups in KE CSA per FFM (RT: 2.15±0.2 vs UT: 2.11±0.25 cm2/kgFFM). Compared with UT, RT had higher leg extension power (W, W/cm2CSA) by 42%, 23% (RT vs UT; 1256±247 vs 887±219 W, 10.4±1.5 vs 8.4±1.6 W/cm2CSA, p<0.001, respectively). Trunk flexion force in RT was also 44% higher than that in UT (RT: 421±56 vs UT: 292±57 N, p<0.001), but in trunk force expressed by N/cm2CSA, no significant difference was observed between the two groups (RT: 14.2±2.1 vs UT: 14.3±3.0 N/cm2CSA). CONCLUSIONS: These results provide possibility that rowing exercise prevents the wasting and weakness of major psoas muscle in elderly men.