It is generally reported that both ageing, and inactivity, which generally increases with age (Troiano et al, 2008), are associated with a decline in neuromuscular function. In order to eliminate the effects of inactivity and on ageing processes highly active, healthy older adults should be studied (Lazarus & Harridge, 2010). In addition, with ageing research there is a reliance on cross-sectional studies which can have large inter-subject variation in many physiological measures.  Thus, the relationship between neuromuscular function and healthy ageing is still not fully clear.  Nine years ago, a cross sectional study of master cyclists aged 55–79 was undertaken (Pollock et al., 2015) with numerous neuromuscular indices measured.  In the present study a number of these cyclists were re-tested in a longitudinal investigation of the effects of healthy active ageing on neuromuscular function.
Fifteen highly active master cyclists (male=14, female=1) now aged 74±6 years returned to the laboratory. Body composition was measured using dual-energy X-ray absorptiometry (DEXA). Neuromuscular testing comprised: nerve conduction velocity (NCV) of the peroneal nerve, assessment of motoneuron excitability via the H-reflex in the soleus, maximal voluntary isometric strength (MVT) and voluntary activation (VA) of the knee extensors (using the twitch interpolation technique), grip strength, peak explosive cycling power (PP) and the timed up and go (TUG). All data are presented as mean±SD and compared pre and post 9 years using paired t-tests.
On re-testing, cycling volume was unchanged (585±388 versus 570±407 km/month; p=0.88).  However, total body mass (69.2±7.1 versus 67.0±6.8 kg; p=0.009) and fat free mass (FFM; 54.8±4.6 versus 50.5±4.1 kg; p<0.001) showed significant reductions of 3% and 8%, respectively, whilst fat mass increased by 15% (14.4±3.5 versus 16.5±3.7 kg; p=0.005). NCV (42.8±4.9 versus 39.2±8.4 m.s-1, p=0.06), H reflex (H-wave/M-wave: 0.35±0.29 versus 0.29±0.26; p=0.25) and VA (90.5±7.5 versus 90.2±5.7 %; p=0.86) were unchanged. MVT (167.8±49.4 versus 152.6±34.7 Nm; p=0.30), grip strength (459.2±71.6 versus 442.5± 68.5 N; p=0.32) and performance in the TUG (5.28±0.69 versus 4.99±0.84 seconds; p=0.25) were also unchanged after nine years of ageing. However, PP decreased significantly in absolute terms by 11% (1028±150 versus 913±171 W; p<0.001), with this age-related decline being reduced (8%) when PP was expressed relative to body mass (14.9±2.2 versus 13.7±2.7 W/kg body mass; p=0.021) and removed when normalised to FFM (18.8±2.3 versus 18.1±3.3 W/kg FFM; p=0.30).
Overall, these data show significant changes in body composition, but a general maintenance of neuromuscular function over nine years of healthy active ageing.  The exception being the decline in PP which was removed when normalised to FFM.