Effects of focus of attention feedback on hip and knee coordination in the learning of the clean weightlifting technique

INTRODUCTION:The learning of motor skills is thought to be enhanced when feedback is focussed on movement outcome (i.e. external focus of attention, EFOA) as opposed to directing attention to specific elements of movement execution (i.e. internal focus of attention, IFOA) (Wulf, 2013). Typical approaches of motor learning have used outcome measures to assess the effects of focus of attention (FOA). However, only a few studies have used dynamical systems quantities to describe coordination changes as a factor of different FOA feedback. The aim of this study was to assess the effect of FOA on Hip x Knee coordination in the learning of the clean weightlifting technique in a group novel to the task.METHODS:Sixteen participants (12 males, 4 females) were randomly assigned to the EFOA or IFOA group (n = 8 each), and were asked to complete a 3-session training protocol consisting of 6 sets x 3 repetitions of the clean with individual feedback provided after each set. Motion capture was used to measure 3D full body kinematics. Right hip and knee flex/ext angles were time registered to 1001 data points and angle-angle plots were built. A modified vector coding technique was used to calculate the coupling angle (CA) between the vector connecting two subsequent data points and the positive horizontal axis. CA at each time point was classified into different coordination patterns (e.g. in-phase, anti-phase) and joint dominancy was identified (e.g. hip, knee) (Needham et al., 2015). Time spent on each coordination at post-test and pre-test was subtracted to define change in coordination. A repeated measure ANOVA (2 Groups x 4 Coordination patterns) was used to assess the effects of FOA on the change of Hip x Knee CA.RESULTS:No Group x Coordination pattern interaction effect was found, suggesting that different type of feedback did not significantly change Hip x Knee CA (F(1.293,42) = 0.056, p = 0.874). Although not significantly, participants of both groups reduced the time spent on an in-phase coordination with knee dominancy (pre- test: EFOA, 47.3%; IFOA, 48.2%; post-test: EFOA, 44.3%; IFOA, 46.5%) and increased the time spent in an in-phase coordination with hip dominancy (pre-test: EFOA, 42%; IFOA, 39.1%; post-test: EFOA, 45.1%; IFOA, 44.4%).CONCLUSION:Hip x Knee coordination was equally affected by EFOA and IFOA in inexperienced participants learning the clean weightlifting technique. These results are potentially explained by the skill level of the participants, as experience was suggested as a mediator of FOA effects (Poolton et al., 2006). Coordination variability analysis may help explain the effects of FOA on coordination and body’s degrees of freedom. Also, studying experienced athletes could further our current understanding of the effects of FOA on coordination.