Effects of practice and preferred rate on perceived exertion, metabolic variables and movement control

One interesting feature of motor skill learning and control is our propensi ty to reduce the metabolic energy cost of achieving the task goal with prac tice and, if unconstrained, to adapt movements to task constraints using an energy-efficient preferred mode. This study investigated the effects of pr eferred rate and practice on metabolic variables, ratings of perceived exer tion (RPE) and movement control. Six healthy well-trained male volunteers w ith no experience of rowing undertook one session per day over 6 days on a Concept II rowing ergometer at a power output of 100 W at preferred stroke rate (PR) and then at experimenter imposed rates of 120% (PR+) and -20% (PR -) of preferred. Heart rate and RPE declined significantly over days and th ere was an associated but nonsignificant reduction in oxygen consumption. H eart rate, oxygen consumption and RPE were significantly lower when rowing at preferred rate and economy was significantly greater. There was a trend toward reduced variability in the rowing cycle duration over practice days but the effect was not significant. Cycle duration was significantly less v ariable in the PR- phase than in the PR and PR+ phases, the latter phases w ere equally variable. Overall the data provide support for the view that mo tor learning is associated with changes to movement control parameters that reflect increased economy of energy expenditure in achieving the task goal . In addition, preferred modes (here preferred rate) appear to be associate d with more economical but not more stable performances than non-preferred. (C) 1999 Elsevier Science B.V. All rights reserved.