0000000000679315
AUTHOR
Johan Lahti
Individual Sprint Force-Velocity Profile Adaptations to In-Season Assisted and Resisted Velocity-Based Training in Professional Rugby
We tested the hypothesis that the degree of adaptation to highly focused sprint training at opposite ends of the sprint Force-Velocity (FV) spectrum would be associated with initial sprint FV profile in rugby athletes. Training-induced changes in sprint FV profiles were computed before and after an eight-week in-season resisted or assisted sprint training protocol, including a three-week taper. Professional male rugby players (age: 18.9 ±
Sprint Acceleration Mechanics in Fatigue Conditions: Compensatory Role of Gluteal Muscles in Horizontal Force Production and Potential Protection of Hamstring Muscles.
Aim: Hamstring muscle injury is the main injury related to sports requiring sprint acceleration. In addition, hamstring muscles have been reported to play a role in horizontal force production during sprint acceleration performance. The aim of the present study was to analyze (i) the determinants of horizontal force production and (ii) the role of hip extensors, and hamstring muscles in particular, for horizontal force production during repeated sprint-induced fatigue conditions. Method: In this experimental laboratory setting study including 14 sprint-trained male athletes, we analyzed (i) the changes in sprint mechanics, peak torque of the knee and hip extensors and flexors, muscle activi…
Effects of internal kinetics and muscle activity during the wide and narrow barbell back squat
Lahti, J. 2017. Effects of internal kinetics and muscle activity during the wide and narrow barbell back squat. Sports biology department, University of Jyväskylä. Master’s thesis. p. 102 (4 attachments). Introduction. The barbell back squat (BBS) is a commonly utilized strength exercise to support general preparedness for the demands in multiple sports. Recently, studies have shown various strength training exercises have the potential to recruit the regions of the hamstrings differently. Specifically, it is unknown if changing stance width under conditions where forward knee movement is restricted engages the hamstring regions differently and how this corresponds with measured 3-D net joi…
Effects of barbell back squat stance width on sagittal and frontal hip and knee kinetics
Different stance widths are commonly utilized when completing the barbell back squat during athletic general preparedness training. Width manipulation is thought to influence sagittal plane stimuli to the hip and knee extensors, the primary extensor musculature in the squat. However, how width manipulation affects frontal plane stimuli is less understood. Knowledge of hip and knee net joint moments (NJM) could improve exercise selection when aiming to improve sport-specific performance and prevent injuries. Fourteen adult amateur rugby athletes were recruited for this study. After a familiarization period, participants performed wide- (WIDE, 1.5× greater trochanter width) and narrow-stance …
Sports analysis, training considerations and applied methods for mixed martial arts
Introduction. Mixed Martial Arts (MMA) is a combat sport and a form of martial art that combines striking and grappling skills. Due to there not being any restrictions between switching from striking to grappling, the sport requires multiple skill sets usually derived from different martial arts. This combined with the fact that MMA requires the athlete to be highly conditioned both from an endurance and strength and power standpoint, places very large challenges on how to optimally design training programs so that individual athletes get the most out of them (Schick et al. 2010, Lenetsky et al. 2012, Alm et al. 2013, Lachlan et al. 2013, Souza-Junior et al. 2015). Psychological factors als…
Multifactorial individualised programme for hamstring muscle injury risk reduction in professional football: protocol for a prospective cohort study
IntroductionHamstring muscle injuries (HMI) continue to plague professional football. Several scientific publications have encouraged a multifactorial approach; however, no multifactorial HMI risk reduction studies have been conducted in professional football. Furthermore, individualisation of HMI management programmes has only been researched in a rehabilitation setting. Therefore, this study aims to determine if aspecificmultifactorial and individualised programme can reduce HMI occurrence in professional football.Methods and analysisWe conducted a prospective cohort study over two seasons within the Finnish Premier League and compare the amount of HMI sustained during a control season to…
Effects of barbell back squat stance width on sagittal and frontal hip & knee kinetics
Different stance widths are commonly utilized when completing the barbell back squat during athletic general preparedness training. Width manipulation is thought to influence sagittal plane stimuli to the hip and knee extensors, the primary extensor musculature in the squat. However, how width manipulation affects frontal plane stimuli is less understood. Knowledge of hip and knee net joint moments (NJM) could improve exercise selection when aiming to improve sport‐specific performance and prevent injuries. Fourteen adult amateur rugby athletes were recruited for this study. After a familiarization period, participants performed wide‐ (WIDE, 1.5× greater trochanter width) and narrow‐stance …
Changes in sprint performance and sagittal plane kinematics after heavy resisted sprint training in professional soccer players
Background Sprint performance is an essential skill to target within soccer, which can be likely achieved with a variety of methods, including different on-field training options. One such method could be heavy resisted sprint training. However, the effects of such overload on sprint performance and the related kinetic changes are unknown in a professional setting. Another unknown factor is whether violating kinematic specificity via heavy resistance will lead to changes in unloaded sprinting kinematics. We investigated whether heavy resisted sled training (HS) affects sprint performance, kinetics, sagittal plane kinematics, and spatiotemporal parameters in professional male soccer players.…
Training at maximal power in resisted sprinting: Optimal load determination methodology and pilot results in team sport athletes.
Aims: In the current study we investigated the effects of resisted sprint training on sprinting performance and underlying mechanical parameters (force-velocity-power profile) based on two different training protocols: (i) loads that represented maximum power output (Lopt) and a 50% decrease in maximum unresisted sprinting velocity and (ii) lighter loads that represented a 10% decrease in maximum unresisted sprinting velocity, as drawn from previous research (L10). Methods: Soccer [n = 15 male] and rugby [n = 21; 9 male and 12 female] club-level athletes were individually assessed for horizontal force-velocity and load-velocity profiles using a battery of resisted sprints, sled or robotic r…