Introduction 

Impairments in balance and functional mobility, as well as reduced nerve conduction velocity and motor neurone excitability have been reported in older people (1). However, the extent to which ageing and physical inactivity interact to determine these remains unclear. To address this, the current study utilised a number of neuromuscular indices in two groups of older individuals i)

older exercisers (cyclists) and ii) non-exercising older males and females.    

 

Methods  

A total of 120 healthy, older males and females aged 64-86 years were recruited. Forty-four male amateur road cyclists (M-C,72±6 years; Height 1.74±0.06m; weight 74.2±9.6kg) and 26 female cyclists (F-C, 71±6 years; height 1.62±0.05m; weight 58.8±6.1kg). In addition, 22 male older non-exercisers (M-ONE, 71±5 years; height 1.75±0.07m; weight 80.6±8.5kg) and 28 female (F: F-ONE; 71±6 years; height 1.60±0.06m) were tested. Single leg balance testing with eyes open (with measurement of anterior-posterior and medio-lateral sway) and with eyes closed (with measurement of time) was undertaken using a balance platform. Peroneal nerve conduction velocity and motor neurone excitability (H-reflex; ratio of H-max to M-max) were both measured, as was TUG.  An incremental exercise test was used to determine aerobic power (VO_2peak).  The data (mean±SD) were analysed using a two-factor ANOVA.  

 

Results 

The cyclists had a significantly higher VO_2peak compared to the non-exercisers (35.7±7.5 versus 22.5±6.0 ml.kg^-1min^-1, p<0.001,).  There were no differences between cyclists and non-exercisers in the amount of sway during the eyes open balance test, but females had lower values in both medio-lateral (M-C 6.0 ±1.4; F-C 4.8±0.9; M-ONE 6.9±2.1; F-ONE 5.0±1.7 mm; p<0.001)  and anterior-posterior directions (M-C  6.5±1.7; F-C 5.3±1.2; M-ONE 6.9±2.9; F-ONE 6.6±2.1mm; p<0.01).  The balance time during the eyes closed test was not different between cyclists and non-exercisers or between males and females (M-C 5.1±2.6; F-C 5.2±2.8; M-ONE 4.2±2.1; F-ONE 5.1±3.3 s). There was no difference in peroneal nerve conduction velocity between the cyclists and the non-exercisers, but was significantly (p<0.05) faster in females compared to the males (M-C 38.0± 7.9; F-C 44.0± 7.7 M-ONE 37.2±10.0; F-ONE 39.5±8.3 ms^-1). In the cyclists, motor neurone excitability was significantly (p<0.05) higher compared to the non-exercisers, but there was no difference between males and females (M-C 0.27±0.20; F-C 0.33±0.23; M-ONE 0.24±0.22; F-ONE 0.15±0.15). For the TUG test the cyclists had significantly (p<0.01) lower times compared to the non-exercisers, but there was no difference between males and females (M-C 5.2±0.7; F-C 5.2±0.8; M-ONE 5.6±1.3; F-ONE 5.9±1.3 s).

 

Conclusion 

These data suggest that some aspects of functional mobility and neural function can be influenced by physical activity status during ageing.  They support the suggestion that ageing results from a mosaic of interacting physiological function and re-emphasise the inadvisability of using physiological indices from inactive participants as epitomising optimal physiological values for ageing.