Limb force and non-sagittal plane joint moments during maximum-effort curve sprint running in humans

Abstract

SUMMARYCompared with running straight, when human runners sprint along a curve, the ability of the inside leg to generate force is compromised. This decreased force generation has been suggested to limit the overall performance of the runner. One theory for this force loss is that the large non-sagittal plane joint moments of the inside leg reach their operating limits, thus prohibiting further generation of the performance-related sagittal plane joint moments. We investigated the inside leg force generation and the ankle and knee joint moments when 13 subjects sprinted with and without an additional mass of 12.4kg along a curve of 2.5m radius. The increase in the subjectsʼ mass evoked a significant increase in the resultant ground reaction force. The peak nonsagittal plane moments increased significantly for both the ankle and knee joints. This observation suggests that when sprinting normally with maximum effort, the non-sagittal plane joint moments are not operating at their limits. The large increases in ground reaction force were associated with greater extension moments generated at the knee joint. In contrast, the peak ankle plantarflexion moment remained unchanged across conditions. It is possible that for the specific joint configuration experienced, the overall ability to generate plantarflexion moment reaches the limit. Future studies with interventions increasing the ability of the muscle-tendon units to generate plantarflexion moment may provide an experimental opportunity to further examine this speculation.

Maximum-speed curve-running biomechanics of sprinters with and without unilateral leg amputations

“…But, stride frequency data for sprinters with a leg amputation do not indicate clear stride frequency enhancements Kram et al, 2010). In addition, RSP are torsionally stiff and resist inversion/eversion, which may impede the optimal inversion and eversion necessary for unbanked curve running (Greene, 1987;Luo and Stefanyshyn, 2012). …”

“…However, because it is difficult to motivate and control the behavior of non-human animals, human running experiments have provided a practical test-bed for exploring the biomechanics of high-speed locomotion on curves. In humans, compared with straight running, maximum running speed is slower on unbanked curves and related to curve radius (Chang and Kram, 2007;Churchill et al, 2015;Ferro and Floria, 2013;Greene, 1985;Luo and Stefanyshyn, 2012). For example, human maximum speed on a 6 m radius unbanked curve is ∼26% slower than straight running (Chang and Kram, 2007).…”

Biomechanics research and sport equipment development

“…The results of Luo and Stefanyshyn [24] did not support either of the aforementioned theories on the limitations of curved sprinting performance. Instead, their results indicated that the sagittal plane ankle joint moments may be the limiting factor, as the ankle plantarflexion moment did not change even with the presence of the additional mass.…”

“…Previous research has also reported this finding [25] and it has been shown that during running, the soleus and gastrocnemius muscles are the primary contributors to the ankle joint [26]. During curved running, the inside foot was in an everted position during the stance phase [24] and it has been speculated that as the ankle joint moves away from its neutral alignment (into eversion or inversion), its ability to generate force decreases. Pilot testing was therefore conducted to determine if ankle plantarflexor force was restricted as the ankle joint entered eversion or inversion.…”

“…In a study by Luo and Stefanyshyn [24], these two mechanisms were investigated by having thirteen athletes perform curved sprinting with and without wearing a vest containing an external mass (*17 % of the athletes' body mass). During curved sprinting with the external mass, the ground reaction force significantly increased indicating that the supporting limb possessed additional ability for force generation.…”