The acceleration kinematics of cricket-specific starts when completing a quick single

Callaghan

Moreno

et al. 2017

Sports

The close-grip bench press (CGBP) is a variation of the traditional bench press (TBP) that uses a narrower grip (~95% of biacromial distance (BAD)) and has potential application for athletes performing explosive arm actions from positions where the hands are held close to the torso. Limited research has investigated CGBP mechanics compared to the TBP. Twenty-seven resistance-trained individuals completed a one-repetition maximum TBP and CGBP. The TBP was performed with the preferred grip; the CGBP with a grip width of 95% BAD. A linear position transducer measured lift distance and duration; peak and mean power, velocity, and force; distance and time when peak power occurred; and work. Pre-sticking region (PrSR), sticking region, and post-sticking region distance and duration for each lift was measured. A repeated measures ANOVA was used to derive differences between TBP and CGBP mechanics (p < 0.01); effect sizes (d) were also calculated. A greater load was lifted in the TBP, thus mean force was greater (d = 0.16–0.17). Peak power and velocity were higher in the CGBP, which had a longer PrSR distance (d = 0.49–1.32). The CGBP could emphasize power for athletes that initiate explosive upper-body actions with the hands positioned close to the torso.

Section: Methodsmentioning

confidence: 99%

An Investigation of the Mechanics and Sticking Region of a One-Repetition Maximum Close-Grip Bench Press versus the Traditional Bench Press

Callaghan

Moreno

et al. 2017

Sports

“…Means ± standard deviations (SD) were calculated, in addition to 95% confidence intervals (CI). Stem-and-leaf plots were used to determine whether there were any outliers in the data for each variable [ 21 , 22 , 52 , 53 ], and outliers were treated via a winsorization method [ 21 , 22 , 53 , 54 , 55 , 56 ]. Paired samples t-tests were used to calculate any significant differences between the dominant and non-dominant legs for peak and mean power, force, and velocity for the BSS.…”

Section: Methodsmentioning

confidence: 99%

Between-Leg Mechanical Differences as Measured by the Bulgarian Split-Squat: Exploring Asymmetries and Relationships with Sprint Acceleration

Risso

Lazar

et al. 2017

Sports

Between-leg strength differences can negatively influence sprint acceleration. The challenge is to find a method to measure this within a unilateral exercise. This study analyzed a five repetition-maximum (5RM) Bulgarian split-squat (BSS) to identify between-leg differences for the dominant and non-dominant legs in peak and mean power, force, and velocity as measured by a linear position transducer. Between-leg differences in these variables were correlated with 20-m (0–5, 0–10, 0–20 m intervals) sprint velocity. Eight men were assessed in the 5RM BSS and 20-m sprint. T-tests calculated between-leg differences in power, force, and velocity. Spearman’s correlations calculated relationships between the between-leg differences in the mechanical variables with velocity over each interval. When comparing the dominant and non-dominant legs, there were significant (p = 0.002–0.056) differences in 11 of 12 variables. However, percentage differences were low (~0.3–12%). There was one large, non-significant correlation (best repetition mean force between-leg difference and 0–5 m velocity; ρ = −0.810) out of 36 relationships. The BSS can provide a profile of between-leg differences in power, force, and velocity. There were limited relationships between the BSS between-leg differences and 20-m sprint velocities. Smaller between-leg differences in BSS power, force, and velocity could ensure minimal impact on acceleration.

“…Contact time is the duration when a leg is in ground support; flight time is the period when the athlete is airborne. Previous research has illustrated the importance of both a high step length ( Callaghan et al, 2014 ; Lockie et al, 2013 ) and frequency ( Lockie et al, 2011 ; Murphy et al, 2003 ) for acceleration. Lower contact times have also been linked to efficient acceleration ( Lockie et al, 2011 ; Murphy et al, 2003 ).…”

Section: Introductionmentioning

confidence: 99%

Interaction Between Leg Muscle Performance and Sprint Acceleration Kinematics

Journal of Human Kinetics

Jalilvand

Callaghan

et al. 2015

Self Cite

This study investigated relationships between 10 m sprint acceleration, step kinematics (step length and frequency, contact and flight time), and leg muscle performance (power, stiffness, strength). Twenty-eight field sport athletes completed 10 m sprints that were timed and filmed. Velocity and step kinematics were measured for the 0–5, 5–10, and 0–10 m intervals to assess acceleration. Leg power was measured via countermovement jumps (CMJ), a five-bound test (5BT), and the reactive strength index (RSI) defined by 40 cm drop jumps. Leg stiffness was measured by bilateral and unilateral hopping. A three-repetition maximum squat determined strength. Pearson’s correlations and stepwise regression (p ≤ 0.05) determined velocity, step kinematics, and leg muscle performance relationships. CMJ height correlated with and predicted velocity in all intervals (r = 0.40–0.54). The 5BT (5–10 and 0–10 m intervals) and RSI (5–10 m interval) also related to velocity (r = 0.37–0.47). Leg stiffness did not correlate with acceleration kinematics. Greater leg strength related to and predicted lower 0–5 m flight times (r = −0.46 to −0.51), and a longer 0–10 m step length (r = 0.38). Although results supported research emphasizing the value of leg power and strength for acceleration, the correlations and predictive relationships (r2 = 0.14–0.29) tended to be low, which highlights the complex interaction between sprint technique and leg muscle performance. Nonetheless, given the established relationships between speed, leg power and strength, strength and conditioning coaches should ensure these qualities are expressed during acceleration in field sport athletes.