Comparison of step kinematics of active resisted 30 m sprints between experienced male and female sprinters

Author's accepted version (postprint). This is an Accepted Manuscript of an article published by Wiley in Translation Sports Medicine on 28/1272019. Available online: https://onlinelibrary.wiley.com/doi/epdf/10.1002/tsm2.130acceptedVersio

COMPARISON OF JOINT KINEMATICS BETWEEN DIFFERENT RESISTED SPRINT LOADS WITH DIFFERENT PHASES OF ACCELERATION OF NORMAL SPRINTS IN EXPERIENCED SPRINTERS

The purpose of this study was to compare joint kinematics of different active resisted loads upon different phases of the acceleration (similar velocity) of a normal sprint. Fifteen experienced male sprinters performed a 50-m sprint with maximal effort from a start block, followed by a 10, 20, 30m with resisted sprints provided by a robotic pully system that gave resp. 65, 50, 25 and 10% reduction of peak velocity, while joint kinematics were measured. The main findings were that in the contact phase most kinematics were similar between the two. During the flight phase maximal hip and knee flexion and velocity were significantly higher in the resisted sprints compared with normal sprint, especially with high resisted loads. It was concluded that most joint kinematics of different active resisted loads are comparable with the different phases of the acceleration of a normal sprint

A KINEMATIC ANALYSIS OF THE STICKING REGION IN FULL BACK SQUATS

The purpose of this study was to investigate 3D kinematics around the sticking region (the weakest region) in full back squats. Eleven resistance-training males (age 23.5 ± 2.6 years, body mass 86.8 ± 21 kg, body height 1.81 ± 0.08 m) performed 6-RM full back squats and the last repetition was taken for further analyses of 3D kinematics around the sticking region. The main findings were that all participants exhibited a sticking region during the last repetition of 6-RM squatting. Timing of the peak and minimal angular velocities of the hip extension, knee extension and plantar flexion movements were concomitant with the two peak velocities and minimal velocity of the barbell. It was suggested that timing and activity (power output) between the knee and hip extensors are responsible for the existence of the sticking region

COMPARISON OF STEP-BY-STEP KINEMATICS OF NORMAL AND ASSISTED 60 M SPRINTS WITH DIFFERENT LOADS IN EXPERIENCED SPRINTERS

The purpose of this study was to compare step-by-step kinematics of normal and assisted 60 m sprints with different loads in experienced sprinters. Step-by-step kinematics were measured using inertial measurement units integrated with a 3-axis gyroscope and a laser gun in eleven participants during a normal 60 m sprint and sprints with a 3, 4, or 5kg pulling force. The main findings were that using increased assisted loads resulted in faster 60 m times, which was a result of a higher step velocity caused mainly by longer step lengths. In terms of practical application, it is notable that employing this approach, when using a 5 kg assisted load can help athletes reach higher step velocities and maintain these velocities longer, which could be a training impulse to move the speed barrier upwards

RELATIONSHIP BETWEEN STEP-BY-STEP FOOT KINEMATICS AND SPRINT PERFORMANCE

The purpose of the study was to investigate the relationship between angular foot step-by-step kinematics and sprint performance during a 50 metre sprint in experienced male sprinters. Foot kinematics were measured using IMU devices integrated with a 3-axis gyroscope and a laser gun. The main findings were that maximal angular velocities increased until strides 6-7, where it stabilised. Time from touch down to dorsal flexion velocity was similar over all strides, whereas time from dorsal flexion velocity to toe off decreased until stride 6. Plantar flexion velocities, especially in toe off, showed the greatest associations with sprint times, whereas maximal dorsal flexion velocity presented no association with sprint times. Time from dorsal flexion velocity to toe off from stride 7 onwards determined the sprint performance and were shorter for faster sprinters

The effects of target location upon throwing velocity and accuracy in experienced female handball players

The purpose of this study was to investigate the effect on throwing performance (velocity and accuracy) of experienced female handball players when throwing at four different targets in a handball goal. Thirteen experienced female handball players (age 18.2 ± 1.7 years, height 1.7 ± 0.10 m, mass 68.1 ± 19.6 kg, and training experience 9.5 ± 3.7 years) performed 10 throws from a 7 m distance at each corner of the handball goal with maximal effort. Maximal ball velocity was recorded with a radar gun together with mean radial error, centroid error, and bivariate variable error, as measurements of accuracy. The main findings were that the ball velocity was higher when throwing at targets at the ipsilateral side, compared with the contralateral side, while throwing consistency (bivariate variable error) decreased when throwing at the contralateral side upper corner. No velocity-accuracy trade-off was found between the four targets. Based upon the findings, it is suggested that players throw to the (upper) ipsilateral side of the goal when performing a penalty throw, dependent on the goalkeepers’ position, since the ball velocity is the highest here, without losing accuracy. This gives the goalkeeper less time to react and stop the ball, thereby giving the player the highest chance of scoring.publishedVersionUnit Licence Agreemen

PAP EFFECT OF RESISTANCE AND OVERSPEED RUNNING ON KINEMATICS AND SPRINT PERFORMANCE

The purpose of this study was to examine if there is a post activation potentiation (PAP) effect of resistance and overspeed sprinting upon kinematics and performance of regular 20m sprints. Fifteen female team handball players performed three training protocols: seven normal 20m sprints, or seven sprints alternating between normal and either resistance or overspeed sprints in a session. The main finding was that only resistance runs had a PAP effect on the first normal 20m sprint. However, this was only the case after one resistance run. Using several resistance runs did not have any positive effect upon the normal runs, but causes probably fatigue as shown in the increased contact times and decreased vertical stiffness, step length and rate. Overspeed running did not cause any changes to the normal runs

Effect of active resisted 30 m sprints upon step and joint kinematics and muscle activity in experienced male and female sprinters

Author's accepted version (postprint).This is an Accepted Manuscript of an article published by Routledge (Taylor & Francis group) in Journal of Sports Sciences on 01/12/2020.Available online: https://www.tandfonline.com/doi/pdf/10.1080/02640414.2020.1856463acceptedVersio

COMPARISON OF KINEMATICS IN REPEATED 30 M SPRINTS IN FEMALE SOCCER PLAYERS

The aim of this study was to examine the effect of sprint repetition on running kinematics (step length, frequency, contact and flight time and vertical stiffness) during a repeated sprint ability test in female soccer players. Seventeen subjects performed seven 30m sprints every 30th second in one session. Kinematics was measured with an infrared contact mat and laser gun and running times with an electronic timing device. The main findings were that sprint times increased in the repeated sprint ability (RSA) test. Furthermore, the main changes in kinematics during the RSA test were an increased contact time and decreased step frequency and vertical stiffness, while no change in step length was observed. Employing this approach in combination with laser gun and infrared mat over 30 m makes it very easy to analyse kinematics in repeated sprint ability in training. It was concluded that fatigue induced in repeated 30 m sprints in female soccer players resulted decreased step frequency and increased contact time and decrease vertical stiffness

Comparison of kinematics and muscle activation between push-up and bench press

publishedVersio