Muscle fibre conduction velocity and cardiorespiratory response during incremental cycling exercise in young and older individuals with different training status

Lenti, M.; De Vito, G.; Sbriccoli, P.; Scotto di Palumbo, A.; Sacchetti, M.

doi:10.1016/j.jelekin.2010.02.004

« Previous Next »Journal of Electromyography and Kinesiology
Volume 20, Issue 4 , Pages 566-571, August 2010

Muscle fibre conduction velocity and cardiorespiratory response during incremental cycling exercise in young and older individuals with different training status

M. Lenti
- Department of Human Movement and Sport Sciences, Università di Roma “Foro Italico”, Italy
G. De Vito
- Department of Human Movement and Sport Sciences, Università di Roma “Foro Italico”, Italy
- UCD School of Public Health, Physiotherapy and Population Science, University College Dublin, Ireland
P. Sbriccoli
- Department of Human Movement and Sport Sciences, Università di Roma “Foro Italico”, Italy
A. Scotto di Palumbo
- Department of Human Movement and Sport Sciences, Università di Roma “Foro Italico”, Italy
M. Sacchetti
- Department of Human Movement and Sport Sciences, Università di Roma “Foro Italico”, Italy
- Corresponding author. Address: Department of Human Movement and Sports Sciences, University of Rome “Foro Italico”, Piazza Lauro De Bosis 15, 00135 Rome, Italy. Tel.: +39 0636733281; fax: +39 0636733214.

Received 10 November 2009; received in revised form 26 January 2010; accepted 10 February 2010. published online 04 March 2010.

Abstract

We investigated the effect of ageing and training on muscle fibre conduction velocity (MFCV) and cardiorespiratory response during incremental cycling exercise. Eight young (YT; 24±5 yrs) and eight older (OT; 64±3 yrs) cyclists, together with eight young (YU; 27±4 yrs) and eight older (OU; 63±2 yrs) untrained individuals underwent to an incremental maximal test on a cycle ergometer. Ventilatory threshold (VT), respiratory compensation point (RCP) and maximal oxygen uptake (VO₂max) were identified and MFCV recorded from the vastus lateralis muscle using surface electromyography with linear arrays electrodes.

In YT MFCV increased with the exercise intensity, reaching a peak of 4.99±1.02 [m/s] at VT. Thereafter, and up to VO₂max, MFCV declined. In YU MFCV showed a similar trend although the peak [4.55±0.53m/s] was observed, at 75% of VO₂max an intensity higher than VT (66% of VO₂max). In both YT and YU MFCV did not decline until RPC, which occurred at 78% VO₂max in YU and at 92% VO₂max (P<0.01) in YT. Differently from young individuals, MFCV in older subjects did not increase with exercise intensity. Moreover, maximal MFCV in OU was significantly lower [3.53±0.40m/s;] than that of YT (P<0.005) and YU (P<0.05).

The present study shows that, especially in young individuals, MFCV reflects cardiorespiratory response during incremental dynamic cyclic exercise and hence can be used to investigate motor unit recruitment strategies.

Keywords: Ageing, Training, Surface electromyography, Ventilatory threshold, Respiratory compensation point