Training effects of the FIFA 11+ and Harmoknee on several neuromuscular parameters of physical performance measures

The main purpose of this study was to analyse the training effects of the FIFA 11+ and Harmoknee on several parameters of physical performance measures in youth amateur football players. Forty-one adolescent players were randomised within each team into two groups (team 1: control vs. FIFA 11+; team 2: control vs. Harmoknee). The FIFA 11+ and Harmoknee groups performed the program 3 times a week for 4 weeks; the control groups completed their usual warm-up routines. Thirteen physical performance measures (joint range of motion, dynamic postural control, single legged hop limb symmetry, sprint time, jumping height and agility) were assessed. All physical performance parameters were compared via a magnitude-based inference analysis. Significant between-group differences (in favour of the FIFA 11+ players) were found for dynamic postural control (anterior [2.5%] and posteromedial [7.2%] distances), single legged hop limb symmetry (side-to-side symmetry during a triple hop test [8.3%]), 10 (8.4%) and 20 (1.8%) m sprint times and jumping height (9.1%) neuromuscular outcomes. For the Harmoknee, significant differences (in comparison to its paired control group) were found only for 10 (2.7%) and 20 (2.9%) m sprint times and jumping height (9.7%). Therefore, the main findings of this study suggest exchanging traditional warm-up programmes for the FIFA 11+ in male youth soccer players based on its superior effects on some neuromuscular parameters (sprinting, jumping and stability) of physical performance

Seasonal variation in isokinetic peak torque in youth soccer players

The aim of the study was to investigate the seasonal variation in the strength of the knee flexors and\ud extensors in highly trained youth soccer players. The players (n=16; age 16.7±0.7) were measured at the end\ud of the competitive season, at the beginning of the off-season and during the sixth week of a new competitive\ud season. Isokinetic concentric peak torque was measured at 60°·s-1, 180°·s-1, 360°·s-1 in a sitting position. The\ud testing range of motion was set from 10–90° of knee flexion. Players performed a set of six maximal repetitions\ud for both the dominant and non-dominant limb. Average values of peak torque significantly changed during\ud the observed periods. Significant differences (p<.05) between the three measurement sessions were noted\ud with respect to the knee flexors at all angular velocities. A post-hoc test confirmed a significant increase\ud between the first and the second measurement for flexion in both the dominant (180°·s-1; p=.033) and nondominant\ud legs (360°·s-1; p=.004). A significant increase was also found between the first and the third session\ud for both limbs during the knee flexion at all angular velocities. The results indicate that peak torque values\ud of knee flexors and extensors varied differently in trained youth soccer players depending on muscle group and movement velocity with statistically significant changes in knee flexors only

Active Stretching and Eccentric Length-Tension Relationship of Hamstring Muscles

The purpose of this study was to investigate the acute effect of an active lower limb stretching routine with a sports-related training load on the hamstring eccentric length-tension relationship. 49 recreational sportsmen completed three assessment sessions, an initial familiarization session and two experimental sessions (control and stretching in random order). Immediately after the interventions (stretching or control), eccentric isokinetic peak torque, maximum force angle and total work were measured in prone position. If the alteration of the eccentric length-tension relationship could be used as a primary risk factor of hamstring muscle strains, the findings of the present study tentatively suggest that static stretching would not be able to alter the relative risk of hamstring muscles

Active Stretching and Eccentric Length-Tension Relationship of Hamstring Muscles

The purpose of this study was to investigate the acute effect of an active lower limb stretching routine with a sports-related training load on the hamstring eccentric length-tension relationship. 49 recreational sportsmen completed three assessment sessions, an initial familiarization session and two experimental sessions (control and stretching in random order). Immediately after the interventions (stretching or control), eccentric isokinetic peak torque, maximum force angle and total work were measured in prone position. If the alteration of the eccentric length-tension relationship could be used as a primary risk factor of hamstring muscle strains, the findings of the present study tentatively suggest that static stretching would not be able to alter the relative risk of hamstring muscles

Efecto agudo del estiramiento activo sobre la fuerza y potencia de la flexión y extensión de rodilla Acute effect of active stretching on knee flexion and extension strength and power output

Aim To analyze the acute effect of a short duration active-static stretching protocol on maximal isokinetic strength and power output during concentric and eccentric flexion and extension knee movements in recreational athletes. Method A total of 27 males and 25 females completed three measurement sessions, an initial session of familiarization and two experimental session (control and active stretching in randomized order) with 72–96 hours interval among consecutive sessions. The active stretching protocol consisted in 5 different unilateral exercises designed to stretch the major lower limb muscle groups. Each stretching exercise was performed twice, holding the position during 30s (2 × 30s), with a rest-interval among series, contra-lateral leg and /or exercises of 20s. In the control session no stretching exercises were performed. Immediately after performed both treatments (control and stretching), the isokinetic indexes of peak torque (PT) and average power (AP) were tested during concentric and eccentric flexion and extension knee movements. Results The ANOVA analysis carried out revealed no significant interaction effect between testing sessions (control and stretching) for knee flexion and knee extension peak torque and mean power in both concentric and eccentric muscle contractions. Conclusions Short (2 × 30s per muscle group) pre-exercise active-static lower-limb stretching routine did not elicit stretching-induce reductions in knee flexor and knee extensor isokinetic concentric and eccentric strength

Monitoring practices of training load and biological maturity in UK soccer academies

Purpose: Overuse injury risk increases during periods of accelerated growth, which can subsequently impact development in academy soccer, suggesting a need to quantify training exposure. Nonprescriptive development scheme legislation could lead to inconsistent approaches to monitoring maturity and training load. Therefore, this study aimed to communicate current practices of UK soccer academies toward biological maturity and training load. Methods: Forty-nine respondents completed an online survey representing support staff from male Premier League academies (n = 38) and female Regional Talent Clubs (n = 11). The survey included 16 questions covering maturity and training-load monitoring. Questions were multiple-choice or unipolar scaled (agreement 0-100) with a magnitude-based decision approach used for interpretation. Results: Injury prevention was deemed highest importance for maturity (83.0 [5.3], mean [SD]) and training-load monitoring (80.0 [2.8]). There were large differences in methods adopted for maturity estimation and moderate differences for training-loadmonitoring between academies. Predictions of maturity were deemed comparatively low in importance for bio-banded (biological classification) training (61.0 [3.3]) and low for bio-banded competition (56.0 [1.8]) across academies. Few respondents reported maturity (42%) and training load (16%) to parent/guardians, and only 9% of medical staff were routinely provided this data. Conclusions: Although consistencies between academies exist, disparities in monitoring approaches are likely reflective of environment-specific resource and logistical constraints. Designating consistent and qualified responsibility to staff will help promote fidelity, feedback, and transparency to advise stakeholders of maturity-load relationships. Practitioners should consider biological categorization to manage load prescription to promote maturity-appropriate dose-responses and to help reduce the risk of noncontact injury

Heart Rate Variability : Effect of Exercise Intensity on Postexercise Response

The purpose of the present study was to investigate the influence of two exercise intensities (moderate and severe) on heart rate variability (HRV) response in 16 runners 1 hr prior to (-1 hr) and at +1 hr, +24 hr, +48 hr, and +72 hr following each exercise session. Time domain indexes and a high frequency component showed a significant decrease (p < .001) between -1 hr and +1 hr for severe intensity. The low frequency component in normalized units significantly increased (p <.01) for severe intensity at +1 hr. Only severe exercise elicited a change in HRV outcomes postexercise, resulting in a reduction in the parasympathetic influence on the heart at +1 hr; however, values returned to baseline levels by +24 hr

Optimized versus corrected peak power during friction-braked cycle ergometry in males and females

The aim of this study was to compare optimization and correction procedures for the determination of peak power output during friction-loaded cycle ergometry. Ten male and 10 female sports students each performed five 10- s sprints from a stationary start on a Monark 864 basket- loaded ergometer. Resistive loads of 5.0, 6.5, 8.0, 9.5, and 11.0% body weight were administered in a counterbalanced order, with a recovery period of 10 min between sprints. Peak power was greater and occurred earlier, with less work having been done before the attainment of peak power, when the data were corrected to account for the inertial and frictional characteristics of the ergometer. Corrected peak power was independent of resistive load ( P > 0.05), whereas uncorrected peak power varied as a quadratic function of load ( P > 0.001). For males and females, optimized peak power ( 971 +/- 122 and 668 +/- 37 W) was lower ( P < 0.01) than either the highest ( 1074 +/- 111 and 754 +/- 56 W respectively) or the mean ( 1007 +/- 125 and 701 +/- 45 W respectively) of the five values for corrected peak power. Optimized and mean corrected peak power were highly correlated both in males ( r = 0.97, P < 0.001) and females ( r = 0.96, P < 0.001). The difference between optimized and mean corrected peak power was 37+ 30 W in males and 33 +/- 14 W in females, of which approximately 15 W was due to the correction for frictional losses. We conclude that corrected peak power is independent of resistive load in males and females

Back foot influence on dorsiflexion using three different positions of the weight bearing Lunge test

Objectives To determine whether back foot (BF) position influences dorsiflexion range of motion (DFROM) during three different positions of the weight bearing lunge test (WBLT). Design Randomised, repeated measures design Setting Sports clubs Participants 52 athletes participating in cutting and pivoting sports Main Outcome measures DFROM was obtained using a WBLT in three different BF positions: BF heel in full contact with the floor, BF heel raised off the floor and BF was non weight bearing (NWB). All measurements were obtained using three methods: inclinometer at the tibial tuberosity, toe to wall distance and goniometer angle from the lateral malleolus to the fibula head. Differences between testing positions were determined using a repeated measures one-way ANOVA and reliability analysis was performed using the Intraclass Correlation Coefficient (ICC). Results DFROM was statistically significantly different for all three positions of the WBLT for each measurement technique (P<.001). These results were associated with large effect sizes for all BF positions and measurement techniques. Reliability ICC values were excellent for all measurements (ICC 0.94-0.99). Conclusions Results show that DFROM differs depending upon the position of the BF during the WBLT. Further research is needed to establish the reproducibility of these three BF positions due to the variability observed

Linearity of the scale for mass and volume within the air displacement plethysmograph (BodPod): A Methodological Investigation

Introduction: In order to maintain the accuracy and reliability for both volume and mass measurements of the air displacement plethysmograph (BodPod) on a day-to-day basis, quality assurance processes are undertaken. Given the importance of accurate estimation of body mass and body volume in determining body composition, the aim of this methodological investigation was to further examine the calibration approaches and to independently determine both the linearity and reliability of mass and volume measurements throughout the potential measurement range. Detailed abstract available to download