Physiological responses to sustained isometric contractions during one- and two-armed work. Role of muscle mass on cardiovascular responses to isometric work.

Cardiovascular and ventilatory responses were investigated during one- and two-armed isometric contractions at the same level of maximum voluntary contraction force (MVC). Significant differences were observed in heart rate, blood pressure, pulse arrival time, and oxygen intake in the contractions as compared with each other. These findings contradict the generally accepted view that cardiovascular responses at the same relative force in isometric muscle contractions, irrespective of the size of muscle mass engaged, are equal.