Inter- and intra-limb coordination during initial sprint acceleration

Abstract

In complex movements, centre of mass translation is achieved through effective joint and segment rotations. Understanding segment organisation and coordination is therefore paramount to understanding technique. This study sought to comprehensively describe inter- and intra-limb coordination and assess step-to-step changes and between-individual variation in coordination during initial sprint acceleration. Twenty-one highly trained to world class male (100 m PB 9.89-11.15 s) and female (100 m PB:11.46-12.14 s) sprinters completed sprint trials of at least 20 m from which sagittal plane kinematics were obtained for the first four steps using inertial measurement units (200 Hz). Thigh-thigh, trunk-shank and shank-foot coordination was assessed using a modified vector coding and segment dominancy approach. Common coordination patterns emerged for all segment couplings across sexes and performance levels, suggesting strong task constraints. Between-individual variation in inter-limb thigh coordination was highest in early flight, while trunk-shank and shank-foot variation was highest in late flight, with a second peak in late stance for the trunk-shank coupling. There were clear step-to-step changes in coordination, with step 1 being distinctly different to subsequent steps. The results demonstrate that inter-limb coordination is primarily anti-phase and trailing leg dominant while ankle motion in flight and late stance appears to be primarily driven by the foot.

Individualization of Training Based on Sprint Force-Velocity Profiles: A Conceptual Framework for Biomechanical and Technical Training Recommendations

“…The technical characteristics of athletes in category 4 would likely include a limited ability to project their center of mass forward in the initial steps of acceleration, potentially because of an ineffective shin roll (1) yet a relative ability to maintain mechanical effectiveness as velocity increases, despite the D RF slope being more negative than category 1 athletes. This would see the athlete move from a more horizontal to upright posture slower than athletes in category 2 and category 3, due to greater ability to maintain their forward lean at toe off (43) and greater trunk-shank symmetry about the ground (21,22,77).…”

“…This limits force production in the horizontal direction as their center of mass resides closer (above) to the point-of-force transmission (43), emphasizing a greater vertical component to the ground reaction force earlier in the sprint effort. Also, a more perpendicular lower limb shank angle during touchdown has been identified to reduce acceleration performance and differentiate between elite and subelite sprinters (21,77). To improve the technical characteristics of athletes located in category 3, the coach should provide technical cues that focus on a more conducive start position to push greater force horizontally, improve their shin roll, focus on pushing down and back, improve trunk-shank symmetry (21), and slowly raise the torso with each successive step.…”

“…Also, a more perpendicular lower limb shank angle during touchdown has been identified to reduce acceleration performance and differentiate between elite and subelite sprinters (21,77). To improve the technical characteristics of athletes located in category 3, the coach should provide technical cues that focus on a more conducive start position to push greater force horizontally, improve their shin roll, focus on pushing down and back, improve trunk-shank symmetry (21), and slowly raise the torso with each successive step. Recently, Alt et al (1) emphasized the importance of the shin segment's orientation to produce a mechanically efficient acceleration, which appears to support previous studies highlighting the orientation of the body center of mass and subsequent propulsive impulse (43).…”

“…Characteristics of movement and training recommendations to improve technical characteristics of sprint performance(1,4,7,9,(13)(14)(15)22,35,43,51,54,60,79) …”

Speed Training Practices of Brazilian Olympic Sprint and Jump Coaches: Toward a Deeper Understanding of Their Choices and Insights (Part II)

“…Indeed, posture is considered an important factor in every sprint phase (i.e., start, drive/pick-up, and maintenance phase), not only by track and field coaches, but also by researchers and sport scientists (Jones et al, 2009;Ma, 2023;Waters et al, 2019). Consequently, there is a substantial body of research on sprinting posture and the body position, with most studies subdividing this technical element into multiple subfactors (Donaldson et al, 2020;Kugler and Janshen, 2010;Ma, 2023;Miyashiro et al, 2019;Simperingham et al, 2016). However, in most sports, sprinting posture should be trained with a focus on the movements and actions that occur during the two principal running phases: acceleration and near to maximal/maximal speed phases.…”