Analysis of lower limb internal kinetics and electromyography in elite race walking

Abstract

The aim of this study was to analyse lower limb joint moments, powers and electromyography patterns in elite race walking. Twenty international male and female race walkers performed at their competitive pace in a laboratory setting. The collection of ground reaction forces (1000 Hz) was synchronised with two-dimensional high-speed videography (100 Hz) and electromyography of seven lower limb muscles (1000 Hz). As well as measuring key performance variables such as speed and stride length, normalised joint moments and powers were calculated. The rule in race walking which requires the knee to be extended from initial contact to midstance effectively made the knee redundant during stance with regard to energy generation. Instead, the leg functioned as a rigid lever which affected the role of the hip and ankle joints. The main contributors to energy generation were the hip extensors during late swing and early stance, and the ankle plantarflexors during late stance.The restricted functioning of the knee during stance meant that the importance of the swing leg in contributing to forward momentum was increased. The knee flexors underwent a phase of great energy absorption during the swing phase and this could increase the risk of injury to the hamstring muscles.3

The biomechanics of race walking: Literature overview and new insights

“…During ankle joint dorsiflexion, in the early phase of the stance period, the body decelerated while the plantar flexor torque, from 60 to 100% of stance period, is fundamental to gain the forward propulsion (Cairns et al, 1986;White & Winter, 1985), and it is strongly correlated to the speed (Figure 3). However recently Hanley and Bissas (2013) proved that ankle torque is not the only power generator, but hip extensors and ankle plantarflexors moments are also fundamental to accelerate the body centre of mass through an energy transfer from the hip to the ankle via the straightened knee. The absorbing power obtained during the knee flexion before toe off is crucial to provide more time to the swinging leg in order to land ahead and avoid flight phase.…”

“…It can be addressed to a varying reference selection for joint angle measurement: Hanley et al (2011a) estimated pelvic angle using hip joint coordinates, whereas Murray et al (1936) and Cairns et al (1986) calculated the whole angular rotation of the same marker. Differently Murray et al (1983), White and Winter (1985) and Hanley and Bissas (2013) showed hip, knee and ankle joint angular time course during a stride, which may be an important functional parameter for a more complete picture of the locomotion pattern and to provide coaches and athletes with a further technical feedback suitable in training.…”

“…The absorbing power obtained during the knee flexion before toe off is crucial to provide more time to the swinging leg in order to land ahead and avoid flight phase. Moreover Hanley & Bissas (2013) focused their investigation on the functional role of the swinging leg: peak joint moment and power of knee and hip correlated with speed occurred during swing and could be a defining feature of better performances. They also interestingly found no differences in normalized joint moments and power between male and female athletes (Hanley & Bissas 2013).…”

“…Moreover Hanley & Bissas (2013) focused their investigation on the functional role of the swinging leg: peak joint moment and power of knee and hip correlated with speed occurred during swing and could be a defining feature of better performances. They also interestingly found no differences in normalized joint moments and power between male and female athletes (Hanley & Bissas 2013). Finally, the overall increase of joint moments in race walking, demonstrated how the faster speed than walking was reached through a costly muscular activity, also characterized by a different and major activation sequence and timing.…”

“…The mechanical power of lower limbs and the related energy flow were considered the most promising analysis for race walking technique, both to compare its features with normal walking (Cairns et al, 1986;Murray et al, 1983;Preatoni et al, 2006;White & Winter, 1985) and to provide useful suggestions for coaching (Hoga, Ae, Enomoto, & Fujii, 2003;Hoga, Ae, Enomoto, Yokozawa, & Fujii, 2006;Hanley & Bissas, 2013). Compared with walking, race walking showed i) an higher ankle joint moment both in dorsiflexion and plantarflexion, ii) an higher joint moment in knee flexion/hyperextension and iii) a greater hip abduction moment (Cairns et al, 1986).…”