Lower limb joint kinetics during the first stance phase in athletics sprinting: three elite athlete case studies

Bezodis, Neil E.; Salo, Aki; Trewartha, Grant

doi:10.1080/02640414.2013.849000

Cited by 52 publications

(74 citation statements)

References 37 publications

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“…Thus, the present findings do not support the notion that back-side mechanics should be minimised, at least in this group of sprinters. Bezodis et al 5,6 assessed the first step out of the blocks in well-trained sprinters and observed that greater hip extension was associated with higher levels of external power production. Optimal extension in the stance hip joint at lift-off during acceleration is likely important for at least two reasons: i) to ensure maximal utilisation of the hamstrings and glutes and ii) to orient the ground reaction forces more horizontally, particularly when combined with a simultaneous and sufficient knee lift for the swing leg.…”

Section: Discussionmentioning

confidence: 99%

“…The fastest runners maximize their acceleration and maximum sprinting velocities by applying greater mass-specific ground forces, [1][2][3] but research literature has so far provided limited information regarding how sprinting athletes should optimize their movements. Due to technology limitations, experimental kinematic studies have typically focused on the measurement area either around the start, [4][5][6] the acceleration phase [7][8][9][10] or during the maximal velocity phase, [11][12][13] typically assessing 1-3 steps. Only a few scientific studies have investigated the kinematics of athletic sprinting based on high-resolution assessments of >6 steps.…”

Section: Introductionmentioning

confidence: 99%

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On the Importance of “Front-Side Mechanics” in Athletics Sprinting

Haugen¹,

Danielsen²,

Alnes³

et al. 2018

International Journal of Sports Physiology and Performance

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Practitioners have for many years argued that athletic sprinters should optimise front-side mechanics (leg motions occurring in front of the extended line through the torso) and minimise back-side mechanics. This study aimed to investigate if variables related to front-and back-side mechanics can be distinguished from other previously highlighted kinematic variables (spatiotemporal variables and variables related to segment configuration and velocities at touchdown) in how they statistically predict performance. Twenty-four competitive sprinters (age 23.1 ±3.4 yr, height 1.81 ±0.06 m, body mass 75.7 ±5.6 kg, 100-m personal best 10.86 ±0.22 s) performed two 20-m starts from block and 2-3 flying sprints over 20 m. Kinematics were recorded in 3D using a motion tracking system with 21 cameras at a 250 Hz sampling rate. Several front-and back-side variables, including thigh-(r=0.64) and knee angle (r=0.51) at liftoff, and maximal thigh extension (r=0.66), were largely correlated (p<0.05) with accelerated running performance (ARP), and these variables displayed significantly higher correlations (p<0.05) to ARP than nearly all the other analysed variables. However, the relationship directions for most front-and back-side variables during accelerated running were opposite compared to how the theoretical concept has been described. Horizontal ankle velocity, contact time and step rate displayed significantly higher correlation values to maximal velocity sprinting (MVS) than the other variables (p<0.05), and neither of the included front-and backside variables were significantly associated with MVS. Overall, the present findings did not support that front-side mechanics were crucial for sprint performance among the investigated sprinters.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

On the Importance of “Front-Side Mechanics” in Athletics Sprinting

Haugen¹,

Danielsen²,

Alnes³

et al. 2018

International Journal of Sports Physiology and Performance

View full text Add to dashboard Cite

show abstract

“…Power was calculated by multiplying the moment by the joint angular velocity; positive power indicated that mechanical energy was being generated, whereas negative power indicated energy absorption (White & Winter, 1985). The amount of work done at each joint was calculated as the time integral of the power curve using the trapezoidal rule (Bezodis et al, 2014).…”

Section: Discussionmentioning

confidence: 99%

“…The results showed an optimal cut-off frequency ranging from 47 -52 Hz in all three force directions, so 50 Hz was chosen as the cut-off frequency. However, because errors have been found to occur during initial contact in similar movements such as sprinting (Bezodis, Salo, & Trewartha, 2014), the first 60 ms of the GRF data were filtered at 10 Hz to match the low cut-off frequencies of the kinematic data and therefore minimise inaccuracies during impact (Bisseling & Hof, 2006).…”

Section: Discussionmentioning

confidence: 99%

Analysis of lower limb work-energy patterns in world-class race walkers

Hanley

Bissas

2016

Journal of Sports Sciences

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The aim of this study was to analyse lower limb work patterns in world-class race walkers. Seventeen male and female athletes race walked at competitive pace.Ground reaction forces (1000 Hz) and high-speed videos (100 Hz) were recorded and normalised joint moments, work and power, stride length, stride frequency and speed estimated. The hip flexors and extensors were the main generators of energy (24.5 J (± 6.9) and 40.3 J (± 8.3) respectively), with the ankle plantarflexors (16.3 J (± 4.3)) contributing to the energy generated during late stance. The knee generated little energy but performed considerable negative work during swing (-49.1 J (± 8.7)); the energy absorbed by the knee extensors was associated with smaller changes in velocity during stance (r = .783, P < .001), as was the energy generated by the hip flexors (r = -.689, P = .002). The knee flexors did most negative work (-38.6 J (± 5.8)) and the frequent injuries to the hamstrings are probably due to this considerable negative work. Coaches should note the important contributions of the hip and ankle muscles to energy generation and the need to develop knee flexor strength in reducing the risk of injury.3

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“…planting the stance foot more posterior relative to the centre of mass (CM) at touchdown, facilitated a forward leaning position and the generation of greater horizontal propulsive forces. The knee joint has been linked to forward lean during the first stance phase (Debaere, Delecluse, Aerenhouts, Hagman, & Jonkers, 2013) and knee extensor moments and powers have recently been identified as an important feature of the first stance phase in well-trained and international-level sprinters (Bezodis, Salo, & Trewartha, 2014;Charalambous, Irwin, Bezodis, & Kerwin, 2012;Debaere et al, 2013). It is therefore possible that any effects of touchdown distance on early acceleration performance are related to knee joint mechanics at touchdown.…”

Section: Introductionmentioning

confidence: 97%

Understanding the effect of touchdown distance and ankle joint kinematics on sprint acceleration performance through computer simulation

Bezodis

Trewartha

Salo

2015

Sports Biomechanics

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This study determined the effects of simulated technique manipulations on early acceleration performance. A planar seven-segment angle-driven model was developed and quantitatively evaluated based on the agreement of its output to empirical data from an international-level male sprinter (100 m personal best = 10.28 s). The model was then applied to independently assess the effects of manipulating touchdown distance (horizontal distance between the foot and centre of mass) and range of ankle joint dorsiflexion during early stance on horizontal external power production during stance. The model matched the empirical data with a mean difference of 5.2%. When the foot was placed progressively further forward at touchdown, horizontal power production continually reduced. When the foot was placed further back, power production initially increased (a peak increase of 0.7% occurred at 0.02 m further back) but decreased as the foot continued to touchdown further back. When the range of dorsiflexion during early stance was reduced, exponential increases in performance were observed. Increasing negative touchdown distance directs the ground reaction force more horizontally; however, a limit to the associated performance benefit exists. Reducing dorsiflexion, which required achievable increases in the peak ankle plantar flexor moment, appears potentially beneficial for improving early acceleration performance.

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Lower limb joint kinetics during the first stance phase in athletics sprinting: three elite athlete case studies

Cited by 52 publications

References 37 publications

On the Importance of “Front-Side Mechanics” in Athletics Sprinting

On the Importance of “Front-Side Mechanics” in Athletics Sprinting

Analysis of lower limb work-energy patterns in world-class race walkers

Understanding the effect of touchdown distance and ankle joint kinematics on sprint acceleration performance through computer simulation

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