Brazilian Journal of Physical Therapy
Print version ISSN 1413-3555
BELASCO JUNIOR, Domingos; OLIVEIRA, Fernando R; SERAFINI, José A. N and SILVA, Antonio C. Determination of the power-duration relationship in upper-limb exercises. Rev. bras. fisioter. [online]. 2010, vol.14, n.4, pp. 316-321. ISSN 1413-3555. http://dx.doi.org/10.1590/S1413-35552010000400008.
OBJECTIVES: To determine the power-duration relationship in upper limb exercises and to investigate the relationships between parameters derived from this function with physiological indicators of aerobic fitness. METHODS: Ten healthy men (26.2±2.3 years, 75.0±11.8 kg, 178.2±11.5 cm and 15.0±5.7% body fat) performed a ramped test on an arm cycle ergometer with increments of 20 W/min. Subsequently, five tests with constant load were performed until exhaustion, with 70, 80, 90, 95 and 100% difference between VT1 and VO2peak. The critical power (CP) was obtained by means of linearization of the power-duration function. RESULTS: The power-duration relationship was described using an adjusted function (r=0.98±0.02). The VO2 at CP (2.66±0.62 l/min) was higher than VT1 (1.62±0.38 l/min) and VT2 (2.36±0.59 l/min), but lower than VO2peak (3.06±0.62 l/min). The CP workload (103.0±26 W) was significantly different from VT1 (69.5±21 W) and VO2peak workloads (151.0±26.3), but was no different of VT2 (103.5±30.8 W). The association between critical power and aerobic condition indexes were always significant when expressed as VO2 (0.73 to 0.78, p<0.05) and in W (0.83 to 0.91, p<0.05). Determination of CP in upper-limb dynamic exercises is simple and inexpensive, and can be used by physical therapists for prescribing and evaluating upper-limb training programs. CONCLUSIONS: The power-duration relationship in upper-limb exercises can be described by a hyperbolic function and it is associated with physiological indicators of aerobic fitness.
Keywords : critical power; upper limbs; metabolic thresholds.