Comparative Analysis of Body Composition and Reference Values of Visceral Adipose Tissues in Various American Collegiate Sports

Background: Currently, body composition (BC) assessment is usually performed to diagnose disease states and accurately estimate certain types of tissues. In athletes, performing BC assessments helps gauge training and nutrition programs to see if they are adequately meeting the athlete’s needs to improve performance. Annual Dual Energy X-ray Absorptiometry (DXA) scans before the start of an athlete’s season can help identify an athlete’s preparedness or health before training begins. Objective: To assess the preseason BC of four collegiate sports: Men’s basketball, men’s baseball, women’s volleyball, and women’s soccer, for Fat Mass (FM), bone mineral density BMD), Fat-Free Mass (FFM), and visceral adipose tissue (VAT). Methods: DXA (Lunar iDXA, GE Healthcare) scans were performed before the start of pre-season training for Men’s Basketball, Baseball, Women’s Volleyball, and Women’s Soccer. End-season DXA scans were performed after the end of the regular season for Men’s Basketball and Baseball athletes. Visceral Adipose Tissue was measured using CoreScan software provided by GE and Fat Mass Index (FMI) and Fat-Free Mass Index (FFMI) were calculated from scanned values. Results: Between the various sports, there were several significant differences that were apparent. Height and percentage of Fat Mass (%BF) were significantly different between all sports except Women’s Volleyball and Women’s Soccer. BMI, VAT, and FFMI were significantly different between males and females. Changes over a season showed increased BMD in Men’s Basketball (2.79 to 2.99 Z-score, pre to end of season scan respectively; p \u3c 0.001). No other observations were noticed to be significant. Conclusions: Sports-specific training and sex have large influences on the body composition of athletes. FMI and FFMI are two indices that may have a stronger indication to health than parameters considered for those who are sedentary and non-active. Female athletes have little to no amounts of VAT and this warrants further investigation

Elbow and shoulder joint torques are correlated with body mass index but not game pitch count in youth baseball pitchers

The number of ulnar collateral ligament (UCL) reconstructive (i.e. “Tommy John”) surgeries performed on youth baseball pitchers have more than doubled since 2000 [1]. Routinely pitching while fatigued is considered a leading factor associated with UCL injuries; adolescent pitchers who had elbow or shoulder surgery were 36 times more likely to have routinely pitched with arm fatigue [1]. MLB/USA Baseball Pitch Smart guidelines limit 9-10 yr. old pitchers to a maximum 75 pitches per game, a figure based on long-term studies related to injury prevention [2]. Several studies have shown that pitching kinematics (e.g. elbow flexion/extension and pronation/supination, scapulothoracic internal-external rotation) may change as adult pitchers reach muscular fatigue [3], and such kinematic changes could result in higher elbow and shoulder rotational torques that may increase injury risk [4]. Several biomechanical studies have been done on ~12 yr. old youth pitchers [5,6] but none have been reported at the 9-10 yr. old level. This study aims to predict elbow and shoulder joint torques throughout a simulated game of 75 pitches for 9-10 yr. old youth pitchers and investigate joint torque correlations with pitch count, pitch speed, and body mass index (BMI; kg/m2)

Effects of Game Pitch Count and Body Mass Index on Pitching Biomechanics in 9- to 10-Year-Old Baseball Athletes

Background: Pitching while fatigued and body composition may increase the injury risk in youth and adult pitchers. However, the relationships between game pitch count, biomechanics, and body composition have not been reported for a study group restricted to 9- to 10-year-old athletes. Hypothesis: During a simulated game with 9- to 10-year-old athletes, (1) participants will experience biomechanical signs of fatigue, and (2) shoulder and elbow kinetics will correlate with body mass index (BMI). Study Design: Descriptive laboratory study. Methods: Thirteen 9- to 10-year-old youth baseball players pitched a simulated game (75 pitches). Range of motion and muscular output tests were conducted before and after the simulated game to quantify fatigue. Kinematic parameters at foot contact, maximum external rotation, and maximum internal rotation velocity (MIRV), as well as maximum shoulder and elbow kinetics between foot contact and MIRV were compared at pitches 1-5, 34-38, and 71-75. Multivariate analyses of variance were used to test the first hypothesis, and linear regressions were used to test the second hypothesis. Results: MIRV increased from pitches 1-5 to 71-75 (P = .007), and head flexion at MIRV decreased from pitches 1-5 to 34-38 (P = .022). Maximum shoulder horizontal adduction, external rotation, and internal rotation torques increased from pitches 34-38 to 71-75 (P = .031, .023, and .021, respectively). Shoulder compression force increased from pitches 1-5 to 71-75 (P = .011). Correlations of joint torque/force with BMI were found at every pitch period: for example, shoulder internal rotation (R2 = 0.93, P \u3c .001) and elbow varus (R2 = 0.57, P = .003) torques at pitches 1-5. Conclusion: Several results differed from those of previous studies with adult pitchers: (1) pitch speed remained steady, (2) shoulder MIRV increased, and (3) shoulder kinetics increased during a simulated game. The strong correlations between joint kinetics and BMI reinforce previous findings that select body composition measures may be correlated with pitching arm joint kinetics for youth baseball pitchers. Clinical Relevance: The results improve our understanding of pitching biomechanics for 9- to 10-year-old baseball pitchers and may be used in future studies to improve evidence-based injury prevention guidelines

Effects of Game Pitch Count and Body Mass Index on Pitching Biomechanics in 9-to 10-Year-Old Baseball Athletes

Background: Pitching while fatigued and body composition may increase the injury risk in youth and adult pitchers. However, the relationships between game pitch count, biomechanics, and body composition have not been reported for a study group restricted to 9-to 10-year-old athletes. Hypothesis: During a simulated game with 9-to 10-year-old athletes, (1) participants will experience biomechanical signs of fatigue, and (2) shoulder and elbow kinetics will correlate with body mass index (BMI). Study Design: Descriptive laboratory study. Methods: Thirteen 9-to 10-year-old youth baseball players pitched a simulated game (75 pitches). Range of motion and muscular output tests were conducted before and after the simulated game to quantify fatigue. Kinematic parameters at foot contact, maximum external rotation, and maximum internal rotation velocity (MIRV), as well as maximum shoulder and elbow kinetics between foot contact and MIRV were compared at pitches 1-5, 34-38, and 71-75. Multivariate analyses of variance were used to test the first hypothesis, and linear regressions were used to test the second hypothesis. Results: MIRV increased from pitches 1-5 to 71-75 (P ¼.007), and head flexion at MIRV decreased from pitches 1-5 to 34-38 (P ¼ .022). Maximum shoulder horizontal adduction, external rotation, and internal rotation torques increased from pitches 34-38 to 7175 (P ¼.031, .023, and .021, respectively). Shoulder compression force increased from pitches 1-5 to 71-75 (P ¼.011). Correlations of joint torque/force with BMI were found at every pitch period: for example, shoulder internal rotation (R2 ¼0.93, P \u3c .001) and elbow varus (R2 ¼0.57, P ¼.003) torques at pitches 1-5. Conclusion: Several results differed from those of previous studies with adult pitchers: (1) pitch speed remained steady, (2) shoulder MIRV increased, and (3) shoulder kinetics increased during a simulated game. The strong correlations between joint kinetics and BMI reinforce previous findings that select body composition measures may be correlated with pitching arm joint kinetics for youth baseball pitchers. Clinical Relevance: The results improve our understanding of pitching biomechanics for 9-to 10-year-old baseball pitchers and may be used in future studies to improve evidence-based injury prevention guidelines

Design and implementation of an instrumented pedal for cycling biomechanics research

Cycling is a common, low-impact activity used for recreation, exercise, and rehabilitation. Knee joint loading can be predicted using inverse dynamic analyses of pedal load cell and kinematic data measured during cycling biomechanics experiments. Several studies have successfully measured foot loading at the pedals, e.g. by using custom instrumented pedal spindles outfitted with strain gauges and a potentiometer to measure crank angle [1-3]. Such designs are relatively complex, requiring difficult machining and component fabrication, and require post-processing of strain gauge data. The long-term goal of this study is to calculate knee joint loading and, ultimately, cartilage tissue stress to provide evidence-based prescriptions for rehabilitative and fitness sustainment exercises for those who are at high risk for knee osteoarthritis. The objective of this project was to design, fabricate, and implement an instrumented pedal system using existing load cells for use in cycling biomechanics research. Measured data retrieved from the load cells during cycling experiments will be compared to similar studies to verify that this project was successful

Using OpenSim to predict knee joint moments during cycling

Cycling is a relatively low impact activity conventionally recommended as a rehabilitative or fitness sustaining exercise for patients at a high risk for knee osteoarthritis (OA) [1,2]. Expanding our understanding of knee joint loads is necessary to develop and improve evidence-based prescriptions for cycling as a rehabilitative and fitness therapy that limits the risk for knee OA. OpenSim (www.simtk.org) is an open source biomechanical analysis software that can partition predictions of external joint loads (or net muscle moments) into muscle and joint contact loads [3]. Joint contact loads more accurately represent cartilage tissue loading and hence risk for cartilage damage and/or OA [4]. As a first step towards predicting knee joint contact loads during cycling, we hypothesized that OpenSim can predict external knee joint moments that are consistent with published data [5,6]. To address this hypothesis, we conducted cycling experiments and used OpenSim’s scale tool, inverse kinematics (IK) solver, and inverse dynamics (ID) solver to model the recorded activity