Force, velocity and power relationship of ankle plantar flexors and ankle dorsiflexors in the elderly

• Project/Area Number: 17500438
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Sports science
• Research Institution: University of Hyogo
• Principal Investigator: TOJI Hideki University of Hyogo, School of Human Science Environment, Professor, 環境人間学部, 教授 (50118014)
• Co-Investigator(Kenkyū-buntansha): KANEKO Masahiro Osaka University of Health and Sport Sciences, School of Health and Sport Sciences, Professor, 体育学部, 教授 (00067232)
• Project Period (FY): 2005 – 2006
• Project Status: Completed (Fiscal Year 2006)
• Budget Amount: ¥1,400,000 (Direct Cost: ¥1,400,000); Fiscal Year 2006: ¥300,000 (Direct Cost: ¥300,000); Fiscal Year 2005: ¥1,100,000 (Direct Cost: ¥1,100,000)
• Keywords: aging / maximal isometric strength / maximal velocity / muscle power / cross-sectional area / EMG / 筋パワー / 筋力 / 収縮速度 / 足関節

Research Abstract

The present study aimed to investigate the characteristics of force, velocity and power relations of ankle plantar flexors and ankle dorsiflexors in elderly. The subjects were 15 elderly men (G-aged) and 15 college male students (G-young) Using specially designed apparatus, the force, velocity and resultant power output by the plantar-and dorsi-flexors muscles were measured, and the force-velocity relations were calculated according to Hill's equation: (F+a)(V+b)=(Fmax+a)b. Ante and post cross-sectional area (CSA-ante, CSA-poste) of the lower limb was estimated from the square of the muscle thickness measured by an ultrasonic apparatus. In CSA-poste, no significant difference was observed between the two age groups, however, the CSA-ante was significantly lower in G-aged than in G-young. The maximal power values were significant differences (G-aged < G-young) in Pmax as well as in Fmax and Vmax. Compared with G-young, G-aged showed a greater reduction in Pmax (69.1%) than Fmax (69.5%) and Vmax (82.8%) of the plantar-flexors, and also showed a greater reduction in Pmax (69.4%) than Fmax (81.8%) and Vmax (78.9%) of the dorsi-flexors. The ratios of Fmax/CSA-poste, Pmax/CSA-poste and Vmax/lower limb length of the plantar-flexors were significantly lower in G-aged than in G-young. However the ratios of Famx/CSA-poste and Pmax/Csa-poste Vmax/lower limb length of the dorsi-flexors were no significant in G-aged than in G-young. The force-velocity curves of G-aged tended to be lower than that of the G-young. There were significant differences among G-aged and G-young for Vmax, V_<10>, V_<20>, V_<30>, V_<45> and V_<60> in the dorsi-flexors, however, not for under various %Fmax load in the plantar-flexors. The iEMG and %iEMG of agonist and antagonist for the plantar-and dorsi-flexors were no significant between G-aged and G-young.
From these results, it was suggested that the ability to develop muscular power may be reduced more functionally than neural factor with increasing age.

Research Products

• [Journal Article] Force, velocity and power relationship of ankle dorsiflexors in the elderly (2007)
  • Author(s): Hideki Toji
  • Journal Title: 58^<th> Conference of Japan Society of Physical Education, Health and Sport Sciences
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Force, velocity and power relationship of ankle plantar flexors in the elderly (2006)
  • Author(s): Hideki Toji
  • Journal Title: 57^<th> Conference of Japan Society of Physical Education, Health and Sport Sciences Pages: 144-144
  • Description: 「研究成果報告書概要(欧文)」より