Plantar flexor activation capacity and H reflex in older adults: Adaptations to strength training

G. Scaglioni, A. Ferri, A. E. Minetti, A. Martin, J. Van Hoecke, P. Capodaglio, A. Sartorio, M. V. Narici

Research output: Contribution to journalArticle

139 Citations (Scopus)

Abstract

The purpose of this study was to investigate whether the voluntary neural drive and the excitability of the reflex arc could be modulated by training, even in old age. To this aim, the effects of a 16-wk strengthening program on plantar flexor voluntary activation (VA) and on the maximum Hoffman reflex (Hmax)-to-maximum M wave (Mmax) ratio were investigated in 14 elderly men (65-80 yr). After training, isometric maximum voluntary contraction (MVC) increased by 18% (P <0.05) and weight-lifting ability by 24% (P <0.001). Twitch contraction time decreased by 8% (P <0.01), but no changes in half relaxation time and in peak twitch torque were observed. The VA, assessed by twitch interpolation, increased from 95 to 98% (P <0.05). Pretraining VA, also evaluated from the expected MVC for total twitch occlusion, was 7% higher (P <0.01) than MVC. This discrepancy persisted after training. The interpolated twitch torque-voluntary torque relationship was fitted by a nonlinear model and was found to deviate from linearity for torque levels > 65% MVC. Compared with younger men (24-35 yr), the Hmax-to Mmax ratio and nerve conduction velocity (H index) of the older group were significantly lower (42%, P <0.05; and 29%, P <0.001, respectively) and were not modulated by training. In conclusion, older men seem to preserve a high VA of plantar flexors. However, the impaired functionality of the reflex pathway with aging and the lack of modulation with exercise suggest that the decrease in the Hmax-to Mmax ratio and H index may be related to degenerative phenomena.

Original languageEnglish
Pages (from-to)2292-2302
Number of pages11
JournalJournal of Applied Physiology
Volume92
Issue number6
Publication statusPublished - 2002

Fingerprint

H-Reflex
Abnormal Reflexes
Resistance Training
Reflex
Neural Conduction
Exercise

Keywords

  • Aging
  • Exercise
  • Triceps surae
  • Twitch interpolation

ASJC Scopus subject areas

  • Physiology
  • Endocrinology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

Cite this

Scaglioni, G., Ferri, A., Minetti, A. E., Martin, A., Van Hoecke, J., Capodaglio, P., ... Narici, M. V. (2002). Plantar flexor activation capacity and H reflex in older adults: Adaptations to strength training. Journal of Applied Physiology, 92(6), 2292-2302.

Plantar flexor activation capacity and H reflex in older adults : Adaptations to strength training. / Scaglioni, G.; Ferri, A.; Minetti, A. E.; Martin, A.; Van Hoecke, J.; Capodaglio, P.; Sartorio, A.; Narici, M. V.

In: Journal of Applied Physiology, Vol. 92, No. 6, 2002, p. 2292-2302.

Research output: Contribution to journalArticle

Scaglioni, G, Ferri, A, Minetti, AE, Martin, A, Van Hoecke, J, Capodaglio, P, Sartorio, A & Narici, MV 2002, 'Plantar flexor activation capacity and H reflex in older adults: Adaptations to strength training', Journal of Applied Physiology, vol. 92, no. 6, pp. 2292-2302.
Scaglioni, G. ; Ferri, A. ; Minetti, A. E. ; Martin, A. ; Van Hoecke, J. ; Capodaglio, P. ; Sartorio, A. ; Narici, M. V. / Plantar flexor activation capacity and H reflex in older adults : Adaptations to strength training. In: Journal of Applied Physiology. 2002 ; Vol. 92, No. 6. pp. 2292-2302.
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