Relation between muscular strength and cardiorespiratory fitness in people with thoracic-level paraplegia

Objectives: To determine the relation between muscular strength, aerobic power (Vo(2)peak), submaximal blood lactate accumulation, and endurance performance in people with thoracic-level paraplegia. Design: Participants performed tests of isokinetic strength, a graded exercise test, and 2 endurance performance tests. A Latin square counterbalanced design was used to determine the order of testing. Setting: Research laboratory in a university setting. Participants: Ten adult male volunteers with thoracic-level paraplegia. Interventions: Not applicable. Main Outcome Measures: The relations between strength, Vo(2)peak, submaximal blood lactate accumulation, and endurance were determined by correlation analysis. Results: Shoulder flexion strength correlated with Vo(2)peak and power output at Vo(2)peak. Shoulder strength accounted for 68.4% of the variation in performance time. Greater isokinetic elbow flexion and extension strength was associated with higher Vo(2) and power output at a blood lactate concentration of 4mmol/L (flexion) and with a greater power output at Vo(2)peak (extension). Conclusions: These findings suggest that in this population, greater muscular strength is associated with greater aerobic power and endurance. Greater muscular strength could exert a positive influence on exercise performance by enabling higher levels of cardiorespiratory stress as the result of reduced or delayed local muscle fatigue. (c) 2005 by American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation.