The effect of arm abduction angle and contraction intensity on perceived exertion

The objective of the present investigation was to examine the effects of voluntary contraction intensity and arm elevation angle on ratings of perceived exertion in healthy young adults. Twelve healthy young adults participated in six separate experimental sessions, during which maximal and sub-maximal arm abduction contractions were performed at one of the following randomly assigned arm angles: 15A degrees, 30A degrees, 45A degrees, 60A degrees, 75A degrees, and 90A degrees arm angles (degrees). The sub-maximal arm abduction contractions (10 s) were performed to target intensities ranging from 10 to 90% of the maximal voluntary contraction (MVC), in randomly ordered 10% increments. Perceived exertion was sampled with a modified Borg category-ratio scale immediately, following each sub-maximal contraction. Voluntary arm abduction torque was significantly (p < 0.05) lower at 45A degrees, 60A degrees, 75A degrees and 90A degrees, as compared to 15A degrees. The ratings of perceived exertion increased significantly (p < 0.05) across the range of contraction intensities, with no significant differences between arm angles. The perceived exertion response, as a function of contraction intensity, was best described as linear across the 30A degrees-90A degrees, while a power function described the response at 15A degrees. The major findings demonstrated that arm position plays a minimal role in mediating the growth in the perceived exertion response, as a function of contraction intensity.