Coach perceptions of FA youth heading guidance: an online survey.

Concerns surrounding the safety of heading within football led the English Football Association (FA) to implement guidelines for youth football participants in February 2020. Information on coach perceptions of guidelines can help to evaluate their suitability.From aninitial 1383 clubs emailed, a total of 351 respondents from English teams spanning ages U12-U18 completed an online survey between August 2020 and January 2021.

Serum neurofilament light concentration does not increase following exposure to low velocity football heading.

: To investigate if heading frequency and impact biomechanics in a single session influence the concentration of serum neurofilament light (NF-L), a sensitive biomarker for axonal damage, up to 7 days after heading incident at ball velocities reflecting basic training drills.: Forty-four males were randomized into either control ( = 8), 10 header ( = 12), 20 header ( = 12) or 40 header ( = 12) groups. Linear and angular head accelerations were quantified during heading.

The effects of barbell load on countermovement vertical jump power and net impulse.

The aim of this study was to examine the effects of barbell load on countermovement vertical jump (CMJ) power and net impulse within a theoretically valid framework, cognisant of the underpinning force, temporal, and spatial components. A total of 24 resistance-trained rugby union athletes (average ± SD: age: 23.1 ± 3.

Agreement between the force platform method and the combined method measurements of power output during the loaded countermovement jump.

There are two perceived criterion methods for measuring power output during the loaded countermovement jump (CMJ): the force platform method and the combined method (force platform + optoelectronic motion capture system). Therefore, the primary aim of the present study was to assess agreement between the force platform method and the combined method measurements of peak power and mean power output during the CMJ across a spectrum of loads. Forty resistance-trained team sport athletes performed maximal effort CMJ with additional loads of 0 (body mass only), 25, 50, 75 and 100% of body mass (BM).

Improving paddling efficiency through raising sitting height in female white water kayakers.

The study compared female white water paddlers over two conditions: with seat raise and with no seat raise. The aim was to determine whether raising the sitting height would improve paddling efficiency. Sitting height of each participant was recorded in order to calculate the seat raise height required and three-dimensional kinematic data was collected for six participants over both conditions.

Magnitude and relative distribution of kettlebell snatch force-time characteristics.

The aim of this study was to compare mechanical output from kettlebell snatch and 2-handed kettlebell swing exercise. Twenty-two men performed 3 sets of 8 kettlebell snatch and 2-handed swing exercise with a 24-kg kettlebell on a force platform. Vertical and horizontal net impulse, mean force, displacement, the magnitude, and rate of work performed displacing the kettlebell-and-lifter center of mass (CM), phase durations and impulse ratio (horizontal to resultant) were calculated from force data.

Kettlebell swing training improves maximal and explosive strength.

The aim of this study was to establish the effect that kettlebell swing (KB) training had on measures of maximum (half squat-HS-1 repetition maximum [1RM]) and explosive (vertical jump height-VJH) strength. To put these effects into context, they were compared with the effects of jump squat power training (JS-known to improve 1RM and VJH). Twenty-one healthy men (age = 18-27 years, body mass = 72.

Barbell kinematics should not be used to estimate power output applied to the Barbell-and-body system center of mass during lower-body resistance exercise.

The aim of this study was to compare measures of power output applied to the center of mass of the barbell and body system (CM) obtained by multiplying ground reaction force (GRF) by (a) the velocity of the barbell; (b) the velocity of the CM derived from three-dimensional (3D) whole-body motion analysis, and (c) the velocity of the CM derived from GRF during lower-body resistance exercise. Ten resistance-trained men performed 3 maximal-effort single back squats with 60% 1 repetition maximum while GRF and whole-body motion were captured using synchronized Kistler force platforms and a Vicon Motus motion analysis system. Repeated measures analysis of variance of time-normalized kinematic and kinetic data obtained using the different methods showed that the barbell was displaced 13.

Mechanical demands of kettlebell swing exercise.

The aims of this study were to establish mechanical demands of kettlebell swing exercise and provide context by comparing them to mechanical demands of back squat and jump squat exercise. Sixteen men performed 2 sets of 10 swings with 16, 24, and 32 kg, 2 back squats with 20, 40, 60, and 80% 1-repetition maximum (1RM), and 2 jump squats with 0, 20, 40, and 60% 1RM. Sagittal plane motion and ground reaction forces (GRFs) were recorded during swing performance, and GRFs were recorded during back and jump squat performances.

A comparison of ballistic and nonballistic lower-body resistance exercise and the methods used to identify their positive lifting phases.

This study compared differences between ballistic jump squat (B) and nonballistic back squat (NB) force, velocity, power, and relative acceleration duration, and the effect that the method used to identify the positive lifting phase had on these parameters. Ground reaction force and barbell kinematics were recorded from 30 resistance trained men during B and NB performance with 45% 1RM. Force, velocity, and power was averaged over positive lifting phases identified using the traditional peak barbell displacement (PD) and positive impulse method.

The effect that side dominance has on barbell power symmetry during the hang power clean.

The aim of this study was to examine whether ground reaction force (GRF) side differences were transmitted and related to bar end power output asymmetries during hang power clean (HPC) performance and whether progressive loading would intensify this effect. Differences between the dominant (D) and nondominant (ND) side average GRFs (AGRFs) of both feet and average bar end power outputs were recorded simultaneously from 15 recreationally trained male volunteers at 30, 60, and 90% 1RM using 2 force platforms and 3 high-speed digital cameras, quantifying side dominance from perceived handedness (left- or right-side dominance [LRSD]), GRF side dominance (force side dominance [FSD]), and bar end power output side dominance (barbell side dominance [BSD]). With the exception of the LRSD condition, differences between the D and ND side AGRFs were significant (FSD: 1.

Does side dominance affect the symmetry of barbell end kinematics during lower-body resistance exercise?

The aim of this study was to examine whether ground kinetic asymmetries significantly affected measures of bar end power output during bilateral lower-body resistance exercise. Vertical ground reaction forces (GRFs) from both feet and power outputs from both ends of the bar were recorded using force platforms and high-speed cameras simultaneously during the back squat performance of 10 experienced male volunteers with 30, 60, and 90% of their 1 repetition maximum. Side dominance was determined according to perceived left- and right-side handedness, dominant left- and right-side GRFs, and barbell power output side dominance.

Biomechanical comparison of unilateral and bilateral power snatch lifts.

Biomechanical characteristics of the one-handed dumbbell power snatch (DBPS) were examined to determine whether significant differences existed between unilateral and bilateral weightlifting movements. Kinetic and kinematic movement data were recorded from 10 male weightlifters (mean +/- SD: age: 30.2 +/- 10.