Exercise physiology provides an understanding of how living organisms function by stressing their body systems maximally. This may be accomplished by simultaneously investigating metabolic and neuromuscular responses. Muscle fiber conduction velocity (MFCV) measured by surface electromyography (EMGs)¹ correlated with percentage of MHC I (r = 0.91) when cycling at lactate threshold power². During a laboratory incremental cycling test different EMGs and cardio-respiratory responses were observed between young and older participants.³ This observation also reflected training induced adaptations³, besides gross efficiency was lower in older than in young cyclists⁴.

An increase in power output in a 6s cycling sprint was observed following an elevation in muscle temperature ([asymp]3°C), which also corresponded to both an augmented rate of ATP turnover and MFCV compared to the control condition⁵. Moreover, the magnitude of the increase in power output (Q10) correlated (r = 0.85) with the content of MHC IIA isoforms⁵.

In conclusion, exercise testing can be used proficiently to gain useful information about the integrated response of the neuromuscular and metabolic systems across the life span, with the ability to discriminate between different levels of performance.

1. Farina D et al. J Appl Physiol. 2004;97:2035-.

2. Farina D et al. J Electromyogr Kinesiol. 2007;17:393-.

3. Lenti M et al. J Electromyogr Kinesiol. 2010;20:566-.

4. Sacchetti M, et al. Med Sci Sports Exerc. 2010;42:2128-.

5. Gray SR, et al.. Am J Physiol Regul Integr Comp Physiol. 2006;290:R376-.