ABSTRACT
A study was conducted to examine the feasibility and validity of using integrated electromyographic signals (IEMG) for determination of anaerobic threshold (AT) in the elderly. Twentynine healthy elderly subjects (aged 67.6±7.7 yr) and twelve young males (aged 23.2±7.9 yr) performed ramp cycle exercise to exhaustion, increasing at a rate of 12.5 W/min for the elderly group and 25.0 W/min for the young group, following 3 min of exercise at zero work load. Myoelectrical signals were measured continuously from the vastus lateralis muscle, and values in terms of IEMG were computed every 10s throughout the test with AID conversion at 500 Hz. For the criterion of IEMG threshold, the breakpoint in the relationship between power output and IEMG was determined by two-segmental linear regression. VT was defined as the VO<SUB>2</SUB> at the onset of a nonlinear increase in VE and/or a sustained rise in VE/VO<SUB>2</SUB> without a rise in VE/VCO<SUB>2</SUB>. It was found that the value of VO<SUB>2</SUB> in terms of IEMGT was similar to VT in both groups, 16.3 and 18.1 ml/kg/min for the elderly group and 33.5 and 36.3 ml/kg/min for the young group, respectively. Furthermore, IEMGT was correlated significantly (p<0.001) with VT in both groups (r=0.871 for the elderly group and r=0.925 for the young group) . It is concluded that the IEMGT method for determination of AT in the elderly is simple and useful.