Decreasing Landing Forces in Children: The Effect of Instructions

Abstract

Study Design: Randomized controlled experimental design. Objectives: To examine the effects of verbal instructions related to control of joint kinematics and auditory feedback on lowering the vertical peak ground reaction forces associated with landing from a jump in children. Background: The majority of children's injuries are associated with activities that involve jumping and landing. Instructions related to joint motion may assist children in decreasing landing forces and thus reduce the chances of sustaining an injury. Methods and Measures: Sixty-one school children whose mean (±SD) age was 9 (±0.89) years participated. The children were randomly assigned (by school) to either experimental (received instruction on lower limb position and auditory cues) or control (received no instruction) groups. Participants were required to step off a box 300 mm in height and land on a force plate. The testing procedure involved 5 sessions. The first 4 sessions were performed over 3 days in the same week, while session 5 was performed approximately 3 months later to assess retention of the skill. The main outcome measure was the peak vertical ground reaction force recorded at foot strike. Results: After instructions, subjects in the experimental group produced lower peak ground reaction forces (PϽ0.05) during landing compared to their control counterparts (ie, sessions 2-4). There was no significant difference (PϽ0.05) between groups at session 5 (3 months postinstruction). Conclusions: Children are capable of assimilating precise instruction to minimize forces on the lower limbs during landing from a jump. Providing further opportunity (ie, more than 1 session) to perform the skill does not alter the magnitude of the effect observed after the initial session of instruction. However, the improvements in landing performance were temporary.

Immediate increases in quadriceps corticomotor excitability during an electromyography biofeedback intervention

“…(Winstein, 1991) Traditionally, feedback has been a type of training technique used to provide participants with a knowledge of results, which is the outcome of the movement, or knowledge of performance, which is a description of the movement quality. (Kernodle and Carlton, 1992) Feedback can be delivered using self-analysis techniques by the same individual receiving the feedback (Oñate et al, 2005), or feedback can be provided via an analysis provided by an expert (Cronin et al, 2008;Prapavessis et al, 2003). Expert provided feedback may rely on oral correction or instruction of different movements.…”

The Effects of a Home-Based Instructional Program Aimed at Improving Frontal Plane Knee Biomechanics During a Jump-Landing Task

“…However, it is most likely that these reductions were too small to be of any clinical significance in reducing knee injury risk. Several technique-training studies have demonstrated temporary reductions in vertical ground reaction forces (13%-27%) using verbal instruction with 6,12,24,27,28 or without 5,23,30,31 feedback. Completion of a 1-week home-based training program did not result in significant changes in peak knee adductor moment or abduction angle compared to baseline values, thus did not result in long-term changes in frontal plane variables.…”

“…These additional instructions to reduce landing forces at the time of testing most likely led to their long-term findings. Prapavessis et al 31 performed a long-term retention test 3 months after their intervention. Unfortunately, their jump-landing instructions did not result in long-term reductions in ground reaction forces.…”

“…36 Previous technique-training studies have used landing instructions that focus the learner's attention internally, 23,30 which may hamper learning. 31 Therefore, the success of technique-training programs may be improved by providing an external focus. Recently, Benjaminse and Otten 2 introduced this concept in the literature as one way to improve ACL injury-prevention programs.…”

Landing Technique and Performance in Youth Athletes After a Single Injury-Prevention Program Session

“…Investigators [42][43][44][45][46] have shown that providing adults and youths with oral cues on which to focus can acutely modify lower extremity movement patterns during a jump-landing task. In agreement with these findings, the youth athletes in our study who completed the IPP achieved relatively more improvement in jump-landing technique than the athletes who completed the other 2 warm-up programs.…”