Peak height velocity

BACKGROUND: During sprinting, the biceps femoris long head predominantly gets injured, while hamstring strengthening exercises predominantly activate the semitendinosus more effectively. Understanding how joint dominance influences hamstring activity may offer clarity on appropriate exercise selection in strengthening programs. PURPOSE: This study compared three hip-dominant hamstring exercises: the rocker, perpetuum mobile fast and slow (PMfast and PMslow) and the Nordic Hamstring exercise (NHE) on their potential to simulate sprint-like activity and kinematics...

The drill-blasting method is a commonly used mining technique in open-pit mines, and the peak particle velocity ( PPV ) caused by blasting vibrations is an important indicator for evaluating the rationality of blasting mining design parameters. To develop an effective PPV prediction model, a parameter self-optimizing RUN-XGBoost prediction model is implemented using the Runge-Kutta optimization algorithm (RUN) combined with extreme gradient boosting (XGBoost). The factors affecting the prediction of PPV , including maximum explosive ( ME ), total explosive ( TE ), blast center distance ( BCD ), blast hole depth ( BHD ), and height difference between the measurement location and the blast location ( DH ), are selected as the influencing indicators...

BACKGROUND: Monitoring of training load is done to improve physical performance and minimize the incidence of injuries. The study examined the correlation between accumulated training load parameters based on periods with maturity (i.e., maturity offset and peak height velocity -PHV- and wellness variables -e.g., stress and sleep quality-). The second aim was to analyze the multi-linear regression between the above indicators. METHODS: Twenty elite young U14 soccer players (M = 13...

We analyzed the effects of load magnitude and bar velocity variables on sensitivity to fatigue. Seventeen resistance-trained men (age=25.7±4.9 years; height=177.0±7.2 cm; body mass=77.7±12.3 kg; back-squat 1RM=145.0±33.9 kg; 1RM/body mass=1.86) participated in the study. Pre- and post-exercise changes in the mean propulsive velocity (MPV) and peak velocity (PV) in the back-squat at different intensities were compared with variations in the countermovement jump (CMJ). CMJ height decreased significantly from pre- to post-exercise (∆%=-7...

This study provides a comprehensive analysis of the physical development patterns from birth to adolescence, utilizing a longitudinal dataset of 70 children monitored from birth until 17 years of age. The research focuses on the variability of growth trajectories, emphasizing the role of genetic and environmental factors in influencing these patterns. Key findings indicate that most children undergo one or two periods of accelerated growth, with significant variability in the timing and magnitude of these growth spurts...

OBJECTIVE: To assess weight velocity and the age at peak weight velocity and to construct weight velocity percentiles in 4-17-year-old apparently healthy Indian children. METHOD: This longitudinal study enrolled 1045 children (588 boys) from Pune belonging to middle and upper socioeconomic class aged 4-17 years. The study parameters included annual height and weight measurements recorded longitudinally from 2007 to 2013. A total of 5225 weight velocity measurements (2940 on boys) were computed...

AIM: The aim of this paper is to determine the relationship between the modified agility T -test (change of direction speed ability), 20-meter sprint test (linear speed ability), and countermovement jump test (vertical jumping performance) in U-14 and professional senior team sports players. METHODS: The sample included 78 (59 female and 19 male) U-14 athletes (age 11.70 ± 1.33 years, height 153.00 ± 12.20 cm and body mass 47...

Existing research on human growth in Mexico is regionally focused, creating a gap in the understanding of growth patterns of children and adolescents at national level and regional variation. The objective of the present study was to characterize the height growth curve of the Mexican population by geographic area and to cluster the states of the Mexican Republic according to their somatic maturation characteristics, based on a national representative sample of boys. Data on age, height, socioeconomic level, and geographic area of 18,219 boys were obtained from the National Health and Nutrition Survey 2012 (ENSANUT) and ENSANUT 2018, carried out in 32 Mexican states...

The objective of the current study was to explore the correlation between repeated sprint sets (RSS) ability and several physical attributes, including maximum sprint speed, maximal aerobic speed, maximal anaerobic speed, aerobic capacity, and explosive strength. Moreover, the aim was to assess the suitability of RSS as a comprehensive evaluation tool for physical qualities and to determine which physical field tests most accurately predict RSS in elite young male soccer players. A total of thirty-two young elite male soccer players (mean age 14...

Petré, H, Tinmark, F, Rosdahl, H, and Psilander, N. Effects of different recovery periods following a very intense interval training session on strength and explosive performance in elite female ice hockey players. J Strength Cond Res XX(X): 000-000, 2024-This study investigates how different recovery periods after high-intensity interval training (HIIT) affects strength and explosive performance during a power training (PT) session. Fifteen female elite ice hockey players (22.5 ± 5.2 years) performed PT, including 6 sets of 2 repetitions (reps) of isometric leg press (ILP) and 6 sets of 3 reps of countermovement jump (CMJ), following a rested state and 10 minutes, 6 hours, or 24 hours after HIIT (3 sets of 8 × 20 seconds at 115% of power output at maximal oxygen consumption on a cycle ergometer)...

Optimal management of cardiovascular disease (CVD) in people with haemophilia (PWH) is a growing issue, given the continuing improvement in life expectancy among PWH. The evolving treatment paradigms targeting higher trough levels and the advent of non-factor replacement therapies (NFRT) means much of the 'protection' PWH were thought to have against CVD may be lost. There is a paucity of evidence regarding the safety of using anticoagulants in PWH. We designed a study assessing the thrombin generation (TG) of PWH of different severities and treatments, compared to non-haemophilia patients receiving a Factor Xa (FXa) inhibitor (apixaban or rivaroxaban), healthy controls, and assessing TG parameters of adding FXa inhibitor to the plasma of PWH receiving emicizumab prophylaxis...

Age at peak height velocity (APHV) is an indicator of maturity timing which is applicable to both sexes, and which is influenced by environmental factors. The objective of this study was to assess variation in APHV associated with several indicators of socioeconomic status (SES) in a longitudinal sample of Polish adolescents. The sample included 739 boys born in 1983 and followed annually from 12 to 16 years, and 597 girls born in 1985 and followed annually from 9 to 13 years. The height records were fitted with the SITAR model to estimate APHV...

OBJECTIVES: This is a cross-sectional study, aimed to develop and cross-validate a fat-free mass (FFM) predictive equation using single-frequency bioelectrical impedance (BIA), considering the predicted age at peak height velocity (PHV) as a variable. Additionally, the study aims to test the FFM-BIA obtained using a previous predictive equation that used skeletal maturity as a variable. METHOD: The participants (n = 169 male adolescent athletes) were randomly divided into two groups: development of a new predictive equation (n = 113), and cross-validation (n = 56)...

PURPOSE: Although spurts in physical capacities during adolescence are well-known, little is known about the existence of such spurts in sport-specific skill development, especially during the period of rapid growth in stature. Our aims were to examine the timing, intensity, and sequence of basketball-specific skill spurts aligned with biological [years from peak height velocity (PHV)] rather than chronological age. We then defined putative sensitive periods (windows of optimal development) for each skill aligned to the adolescent growth spurt...

BACKGROUND: Our aim was to determine if prenatal factors, gestational age, birth weight and length, and childhood body mass index (BMI) are associated with the timing of puberty. METHODS: Our population-based study comprised 4826 girls and 5112 boys born between 1997 and 2002. Multiple linear regression modeled the relationships between the maternal and child predictors and the age at peak height velocity (PHV). RESULTS: Maternal smoking throughout pregnancy was associated with earlier age at PHV (-1...

No studies have reported ground reaction force (GRF) profiles of the repeated depth jump (DJ) protocols commonly used to study exercise-induced muscle damage. Furthermore, while compression garments (CG) may accelerate recovery from exercise-induced muscle damage, any effects on the repeated bout effect are unknown. Therefore, we investigated the GRF profiles of 2 repeated bouts of damage-inducing DJs and the effects of wearing CG for recovery. Nonresistance-trained males randomly received CG (n = 9) or placebo (n = 8) for 72 hours recovery, following 20 × 20 m sprints and 10 × 10 DJs from 0...

UNLABELLED: The present study aimed to estimate the height growth curve for Mexican boys and girls based on their body mass index (BMI) status (normal and overweight/obese) and to develop a height Lambda, Mu, and Sigma (LMS) growth reference for Mexican children aged 2 to 18 years. METHODS: Chronological age and height records (7,097 boys and 6,167 girls) were obtained from the Mexican National Survey of Health and Nutrition database. Height growth curves were fitted using the Preece-Baines 1 (PB1) model and the LMS method...

PURPOSE: Greulich and Pyle is the most used system to estimate skeletal maturity but has significant drawbacks, prompting the development of newer skeletal maturity systems, such as the modified Fels skeletal maturity systems based on knee radiographs. To create a new skeletal maturity system, an outcome variable, termed a "skeletal maturity standard," must be selected for calibration of the system. Peak height velocity and 90% of final height are both considered reasonable skeletal maturity standards for skeletal maturity system development...

INTRODUCTION: The upper body Wingate Anaerobic Test (WAnT) is a 30-second maximal effort sprint against a set load (percentage of body mass). However, there is no consensus on the optimal load and no differential values for males and females, even when there are well-studied anatomical and physiological differences in muscle mass for the upper body. Our goal was to describe the effects of load, sex, and crank position on the kinetics, kinematics, and performance of the upper body WAnT...

Limited analyses based on national samples have assessed whether early attention-deficit/hyperactivity disorder (ADHD) symptoms predict later internalizing and externalizing symptoms in youth and the influence of sex and pubertal timing on subsequent psychiatric symptoms. This study analyzed data ( n = 2818) from the Environmental influences on Child Health Outcomes Program national cohort. Analyses used data from early childhood (mean age = 5.3 years) utilizing parent-reported ADHD symptoms to predict rates of internalizing and externalizing symptoms from late childhood/adolescence (mean age = 11...