Three-dimensional kinetic function of the lumbo-pelvic-hip complex during block start

Abstract

Previous studies on joint kinetics during track and field block starts have been limited to lower-limb sagittal kinetics; however, we hypothesised that lumbopelvic extensors, lateral flexors, and hip abductors also act as substantial energy generators. The present study aimed to examine the three-dimensional lumbo-pelvic-hip kinetics to better understand the generation of mechanical energy during a block start. 3D kinematic and force data during block starts of 10 m maximal sprinting in 12 male sprinters (personal best in a 100 m sprint, 10.78 ± 0.19 s [range, 10.43-11.01 s]) were captured using a motion capture system and force platform. The three-dimensional lumbo-pelvic-hip kinetics were calculated. The peak lumbosacral extension torque (3.64 ± 0.39 Nm/kg) was significantly larger than any other lower-limb and lumbosacral torques (<3.0 Nm/kg). It was suggested that large lumbopelvic extension torques are needed during the block start to anchor the pelvis by cancelling out both hip extension torques acting on the pelvis, leading to hip extensor-induced thigh sagittal rotations rather than pelvic posterior tilt. During the double-stance phase, the lumbosacral extensors generated mechanical energy (0.35 ± 0.16 J/kg, 14 ± 4% of the sum of lumbosacral and lower-limb net joint work). During the single-stance phase, the sum of the net mechanical work by lumbosacral lateral flexors and front hip abductors was 0.35 ± 0.14 J/kg, which comprised 9 ± 3% of the sum of the net joint work. The results lead to the speculation of the importance of strengthening not only the leg extensors, but also the lumbopelvic extensors, lateral flexors, and hip abductors for block starts. Further training studies to verify this speculation will improve training strategies for the track and field block start performance.

Biomechanical Performance Factors in the Track and Field Sprint Start: A Systematic Review

“…Fifteen studies [ 2 , 3 , 10 , 11 , 12 , 17 , 20 , 21 , 23 , 25 , 33 , 34 , 35 , 36 , 37 ] focused specifically on the block phase, 18 studies [ 1 , 4 , 5 , 6 , 7 , 8 , 13 , 14 , 15 , 16 , 18 , 19 , 24 , 38 , 39 , 40 , 41 , 42 ] on the block phase and, at least one of the subsequent two flight and stance phases, and 3 studies [ 9 , 22 , 43 ] on the initial acceleration (the first and/or the second step). A summary of all the individual studies reviewed is presented in Table 1 .…”

“…Study purposes included evaluation of specific block start and initial acceleration variables and their influence on block performance (14 studies) [ 2 , 3 , 4 , 6 , 10 , 11 , 14 , 18 , 23 , 24 , 33 , 36 , 40 , 43 ]; analysis of different “set” position or block configurations (11 studies): location [ 20 ] and modulation [ 35 ] of center of pressure (COP) on the starting block surface, different block spacing [ 8 , 12 , 37 ] and widened conditions [ 21 ], different block plate obliquities [ 19 , 25 , 34 ], changed “set” position knee angles [ 41 ] and block pre-tension [ 17 ]; and comparisons between sprinters of different performance levels, despite the subjectivity associated with the descriptor of the performance level of the athletes (11 studies) [ 1 , 5 , 7 , 9 , 13 , 15 , 16 , 22 , 38 , 39 , 42 ]. The ambiguity in the performance level descriptors includes categories such as: elite vs. sub-elite or well-trained [ 7 , 16 , 22 ], world-class vs. elite [ 38 ], faster vs. slower [ 5 ], adult well-trained vs. trained [ 9 , 15 , 42 ]; elite or well-trained senior vs. junior academy, elite junior, U18 or young well-trained […”

“…Given the importance of the sprint start, a new body of research has emerged in the past two decades that involved advanced technologies, high-precision methods, and sprinters of a higher performance level. For this reason, several technical (kinematic) and dynamic (kinetic) aspects are currently identified as determinant factors for starting block phase and initial sprint acceleration performances [ 1 , 4 , 6 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ]. However, the concepts, outcomes, and findings between studies are sometimes inconsistent and difficult to interpret and conclude from.…”

Achilles Tendon Length Is Not Related to 100-m Sprint Time in Sprinters

“…[31][32][33] The plantar flexor torque may contribute to the block clearance performance more than other lower limb joint torques. 34,35 Additionally, the plantar flexor torque may be the greatest source of positive work during the stance phase of maximum acceleration sprinting among all lower limb joint torques. 36 Further studies are needed to examine the relationships between the AT morphological variables and biomechanical variables (ie, plantar flexor torque) during some phases, especially the block start and acceleration phases, while a 100-m sprinting.…”

No Correlation Between Plantar Flexor Muscle Volume and Sprint Performance in Sprinters

“…Considering their findings, the plantar flexor size may contribute to achieving superior performance during the block start and/or acceleration phases. The plantar flexor torque may play an important role for block clearance performance more than other lower limb joint torques (Brazil et al, 2017 ; Sado et al, 2020 ), which may be related to accelerating sprint velocity during the initial phase while a 100 m sprinting (Macadam et al, 2019 ; Nagahara et al, 2020 ; Sado et al, 2020 ). Furthermore, the plantar flexor torque may be the greatest source of positive work during the stance phase when maximum acceleration sprinting among all joint torques of the lower limb (Schache et al, 2019 ).…”