Objectives: To determine and compare the level of quadriceps activation for knee injured participants during, kinetic open-chain, closed-chain and composite-chain (Slackline) clinical exercises. Quadriceps, activation is a critical component of lower limb movement and subsequently, rehabilitation. However, selective activation can be difficult due to pain, loss of function and impaired neuro-motor activation., Design:, Repeated measures (within-subjects) ANOVA. Methods, Consecutive physiotherapy outpatients (n = 49, 41.8+/-16.8 years, range 13-72 years, 57% female) with, an acute (less than 2 weeks) knee injury were recruited. Participants were assessed for quadriceps activation, using skin mounted electromyography during five separate clinical quadriceps activation exercises:, two open-chain, inner range quads and straight leg raise; two closed-chain, step down and step up; and, a composite-chain, slacklining step-up. Outcome measures were: median score on electromyography as, measured in microvolts (µV); and perceived exertion on an 11-point numerical rating scale. Results:, Median scores of the open- and closed-chain exercises showed no statistical difference, while, composite-chain Slackline exercise showed significantly (p less than 0.0001) higher quadriceps activation, (F(2.52, 121.00) = 21.53, p less than 0.0001) at significantly lower exertion (F(1.62, 77.70) = 26.88, p less than 0.0001)., Conclusions:, The use of Slackline rehabilitation training can provide significant increases in activation and, recruitment of the quadriceps for composite-chain exercises in the clinical setting. This activation, occurs spontaneously at significantly lower levels of perceived exertion. This spontaneous quadriceps, activation in a selective and simple manner is a valuable adjunct exercise for lower limb rehabilitation, programs. This is of particular relevance for the outpatient setting and circumstances where the, quadriceps is inhibited and activation is required.
Journal of Science and Medicine in Sport / Vol. 18, No. 1, pp.62-66