CONTACT TIME, FLIGHT TIME AND GROUND REACTION FORCES DURING A CONTROLLED RUNNING TRIAL OF ELITE AMERICAN FOOTBALL PLAYERS

Running speed is influenced by vertical ground reaction force (vGRF) application, foot-ground contact time (Tc), flight time (TF), and time taken to reposition the limbs in swing. The purpose of this study was to investigate running speed modulators in two groups of elite American football players [Skill (i.e. wide receivers, defensive backs, n=8) and Big Skill (i.e. linebackers, tight ends, n=8)]. Subjects ran at 6.5 m/s for 5 sec on an instrumented treadmill. Peak vGRF, Tc and TF were examined for overall associations and compared between groups. Tc was strongly associated with vGRF, p\u3c.001. Big Skill had larger absolute vGRF, p=.012 than Skill. Skill players had larger TF, smaller TC, and smaller relative vGRF, although not significant. Elite American football players apply large forces over long foot-ground contact time during a controlled ru

BODY COMPOSITION COMPONENTS ARE RELATED TO VERTICAL JUMP KINETICS IN ELITE AMERICAN FOOTBALL PLAYERS

American football players vary in body composition across player positions. Components of body composition may affect jumping performance. The purpose of this study was to investigate the relationships between lean body mass, fat mass, total body mass, vertical jump (VJ) height, VJ reactive strength, and VJ kinetic asymmetry. 39 players had their body composition assessed using a BOD POD and VJ kinetics via a force plate. Pearson correlation coefficients quantified relationships between the variables, allpha =.05. VJ height and reactive strength were highly and very highly negatively associated with lean body mass, fat mass, and total body mass,

EFFECTS OF POST-ACTIVATION POTENTIATION ENHANCEMENT ON JUMP ASYMMETRY USING BANDED SQUATS WITH PROFESSIONAL AMERICAN FOOTBALL PLAYERS

Understanding the effects complex training has on symmetry could potentially supply practitioners with the knowledge to provide safe and effective training for their athletes. The purpose of this study was to determine the effects of post-activation potentiation enhancement (PAPE) using banded squats on symmetry during a countermovement jump (CMJ). Professional American football players (n=8) performed four trials of CMJs on dual force plates to record limb asymmetry and jump height with a set of heavy banded squats between each trial to ensure a potentiation effect was present. There were no significant changes in asymmetry across the 4 trials, p\u3e.05. However, jump height did significantly improve F(3,21) = 3.69, p=0.028. Banded squat training has no effect on jump symmetry

Training, Diet and Supplement Regimen of an Elite Female Standup Paddler in Preparation for an Ultra-distance Event: a Case Study

PURPOSE: Standup paddleboard (SUP) racing is the quintessential power-endurance sport that requires a combination of skill, aerobic power as well as muscular strength and endurance. The purpose of this case study was to examine the training, diet and supplement regimen of an elite paddler in preparation for an ultra-distance Standup paddleboard race (i.e., Molokai to Oahu [M2O) 32-mile open ocean SUP race). METHODS: The physical characteristics of the paddler are as follows: 32-year old female, 167.6 cm height, 62.7 kg weight and 19% body fat (Bod Pod®). During the six-month training program, the athlete\u27s daily average intake of the macronutrients was as follows: protein 151 g/d, carbohydrate 122 g/d and fat 62 g/d. Through this time the athlete incorporated more protein-based supplements pre-and post-training as well as supplementing with beta-hydroxy methylbutyrate (HMB) and beta-alanine. The athlete also incorporated a periodized training plan over the 6 months prior to the race. This included an average distance of run training of 24 miles/month as well paddle training 74 miles/month. Paddling training increased from 64 miles in the first month, eventually working up to 105 miles for the fifth month followed by a taper. The periodized plan was designed to increase paddling mileage 15 to 25% every four weeks and included a mix of various training types such as high intensity interval training, steady state cardio, and sprint training. RESULTS: The interventions listed above, along with a periodization training program resulted in an increase of 2.2 kg body mass and a decrease of 2% body fat. CONCLUSION: The nutritional strategies undertaken included an increased daily protein intake, as well as supplementation with HMB and beta-alanine. Together, these strategies resulted in a 3.16 kg gain in LBM as well as a 2% decrease in body fat. In addition, the prescribed strategies lead to a successful finish of 6th place overall female with a time of 6:37:36 at the M2O Stand-up Paddleboard Championship

RELATIONSHIP OF REACTIVE STRENGTH AND BODY COMPOSITION IN ELITE AMERICAN FOOTBALL PLAYERS

Reactive strength represents the ability to change rapidly from eccentric to concentric contraction and may be influenced by body composition. The purpose of the study was to determine if body mass (BM), lean body mass (LBM), or percent fat mass (%FM) were associated with reactive strength. Twenty-five males undergoing training for the National Football League’s combine had their Reactive Strength Index (RSI) measured from a 4-jump drop jump (DJ) onto an electronic timing mat, and BM, LBM and %FM assessed via a BodPod. Pearson correlation coefficients showed moderate, negative significant correlations between RSI and BM (r(23)=-.531, p=.006), and RSI and LBM (r(23)=-.565, p=.003). RSI was not associated with %FM. Explosiveness appears related to heaviness but not fatness. Coaches may consider effects of body composition modulation on RSI

A three dimensional kinematic comparison of the conventional versus sumo style deadlifts

The primary purpose of this study is to use three-dimensional motion analysis to determine and compare certain kinematic joint and segmental variables at defined events (bar off and knee passing) between the conventional and sumo styles of deadlifts. The secondary purpose of this study is to investigate bar path profiles and vertical bar velocity patterns (including attempting to determine a "sticking region") and compare these variables between the two styles and two sub-maximal loads (50% and 75%). Five subjects performed each style at each load. Each trial was filmed, digitized, and imported for 3-D reconstruction. This data was utilized to determine hip, knee, inter-thigh, trunk, thigh, and shank angles at bar off and knee passing; bar path profiles; and bar velocity values (including determining the "sticking region"). A two way ANOVA showed statistically significant differences between the two styles for most joint and segmental variables at both events and the range between the two events. There was a significant difference between the two styles for total time and horizontal and vertical bar displacement. Only one trial showed a sticking region. Based on the results of this study, it can be stated that kinematic differences do occur between the two styles of deadlifts at submaximal loads. A sticking region does not appear to occur at loads of 75% of a 1 rep maximum or less.Thesis (M.S.)School of Physical Educatio

Post-Activation Performance Enhancement Through Variable Loading Maintains Power Output Over Five Sets in Highly Trained Athletes

The goal was to examine the acute effects of five sets of variable loading (VL) on the post-activation performance enhancement (PAPE) response during a live training session in highly trained athletes. PAPE is the phenomenon where acute improvements in power production in light loaded movements occur post near maximal loaded muscle contraction. PAPE may be induced with VL where resistance in the form of chains or bands is added to the bar as it displaces in the concentric phase. Participants were American football players from a variety of field positions (n=12, height =188 ± 0.01 cm, total body mass = 114.4 ± 24.3 kg) preparing for the 2023 National Football League draft representing during a lower body training session. They performed a contrast PAPE protocol consisting of 2 baseline vertical jumps (VJ) on dual-force plates followed by five sets of heavy VL half-squats using chains alternated with 2 VJs. PAPE did produce practical increases in reactive strength (baseline, 0.66±0.15, set 5, 0.67±0.17 m/s) and decreases in jump height (baseline, 20.3±2.9, set 5, 19.5±2.9 in), absolute peak power (baseline, 8125±1116, set 5, 7988±1038 W), and normalized peak power (baseline, 72.0±6.3, set 5, 71.1±8.7 W/kg). Findings suggest that power was at least maintained over multiple sets of VL induced PAPE. Acute post-activation performance enhancement through variable loading with chains in the strength-speed zone appeared to preserve power output across multiple sets but does not increase power in highly trained athletes

Bone Mineral Density in Competitive Athletes

Introduction: The purpose of this investigation was to characterize the bone mineral density in a wide variety of competitive athletes. Methods: A cohort of 135 athletes was assessed for body composition via dual-energy x-ray absorptiometry (DXA). These included professional mixed martial arts fighters (MMA), elite stand-up paddlers, collegiate football players, collegiate swimmers, collegiate track and field athletes, collegiate and world-class distance runners as well as a group of men and women who participated in regular heavy resistance training. Results: In general, bone mineral density (BMD) as determined by the T-score was highest in mixed martial arts fighters (T-score = 3.1 ± 0.9) and football players (T-score = 2.7 ± 0.7) followed by resistance-trained (RT) males (T-score = 1.9 ± 1.2). RT males had a greater average T-score than RT females (T-score 1.5 ± 1.3). Based on the data from this investigation, we conclude that RT males have greater BMD as determined by the T-score than RT females. Also, MMA fighters and football players are unique in that they tend to demonstrate very high BMD (1.57 ± 0.10 and 1.60 ± 0.12 g/cm2 , respectively) with a concomitantly high T-score. Conclusions: It is evident that the high-impact nature of football and MMA competition is conducive to producing very high bone mineral densities. However, inasmuch as this investigation is cross-sectional in nature, it is not clear if athletes are self-selected for higher bone mineral density and/or if it is the result of years of training in their respective sport