Medicine and Health Sciences Commons^™

Does Fatigue Influence Joint-Specific Work And Ground Force Production During The First Steps Of Maximal Acceleration?, Shayne Vial, Jodie C. Wilkie, Mitchell Turner, Mark Scanlan, Anthony J. Blazevich

Research outputs 2022 to 2026

During initial acceleration, the first steps of a maximal-effort (sprint) run often determine success or failure in the capture and evasion of an opponent, and is therefore a vital factor of success in many modern sports. However, accelerative events are commonly performed after having already run considerable distances, and the associated fatigue should impair muscle force production and thus reduce acceleration. Despite this, the effects of running-induced fatigue on our ability to accelerate as well as the running technique used to achieve it have received little attention. We recorded 3-D kinematics and ground reaction forces during the first three steps …

Fatigue Does Not Increase Limb Asymmetry Or Induce Proximal Joint Power Shift In Habitual, Multi-Speed Runners, Shayne Vial, Jodie Cochrane Wilkie, Mitchell Turner, Anthony J. Blazevich

Research outputs 2022 to 2026

During prolonged jogging, joint moment and work tend to decrease in the distal (ankle) joint but increase at proximal (hip/knee) joints as performance fatigue manifests, and such adaptations might be expected to occur in sprinting. Fatigue is also thought to increase inter-limb asymmetries, which is speculated to influence injury risk. However, the effects of fatigue on sprint running gait have been incompletely studied, so these hypotheses remain untested. Using statistical parametric mapping, we compared 3-D kinematics and ground reaction force production between the dominant (DL) and non-dominant (NDL) legs of 13 soccer players during both non-fatigued and fatigued sprint running. …

Differing Hypertrophy Patterns From Open And Closed Kinetic Chain Training Affect Quadriceps Femoris Center Of Mass And Moment Of Inertia, Jacob E. Earp, Domenic Angelino, Disa L. Hatfield, Vincent Colantuono, Euan R. Jackson, Kristin D. Morgan, Alessandra Adami, Kathleen J. Melanson, Anthony J. Blazevich

Research outputs 2022 to 2026

Purpose: To determine whether kinetic chain pattern during knee extensor strength training influences quadriceps femoris center of mass and moment of inertia about the hip in a predictable manner as such changes can affect running economy. Methods: Twelve participants completed 8 weeks of both unilateral open (OKC) and closed (CKC) kinetic chain resistance training on opposing legs. Changes in quadriceps femoris muscle volume (VOLQF), center of mass location (CoMQF), and moment of inertia (IQF) about the hip were determined from magnetic resonance images scans. Regional hemodynamics of the vastus lateralis taken at 30% and 70% of muscle length during OKC …

Hamstrings Force-Length Relationships And Their Implications For Angle-Specific Joint Torques: A Narrative Review, Eleftherios Kellis, Anthony J. Blazevich

Research outputs 2022 to 2026

Temporal biomechanical and physiological responses to physical activity vary between individual hamstrings components as well as between exercises, suggesting that hamstring muscles operate differently, and over different lengths, between tasks. Nevertheless, the force-length properties of these muscles have not been thoroughly investigated. The present review examines the factors influencing the hamstrings’ force-length properties and relates them to in vivo function. A search in four databases was performed for studies that examined relations between muscle length and force, torque, activation, or moment arm of hamstring muscles. Evidence was collated in relation to force-length relationships at a sarcomere/fiber level and then moment …

Muscle-Specific Contributions To Lower Extremity Net Joint Moments While Squatting With Different External Loads, Kristof Kipp, Hoon Kim, William I. Wolf

Exercise Science Faculty Research and Publications

The purpose of this study was to determine muscle-specific contributions to lower extremity net joint moments (NJMs) during squats with different external loads. Nine healthy subjects performed sets of the back squat exercise with 0, 25, 50, and 75% of body mass as an added external load. Motion capture and force plate data were used to calculate NJMs and to estimate individual muscle forces via static optimization. Individual muscle forces were multiplied by their respective moment arms to calculate the resulting muscle-specific joint moment. Statistical parametric mapping (α = 0.05) was used to determine load-dependent changes in the time series …

Maximal Strength In Relation To Force And Velocity Patterns During Countermovement Jumps, Michael H. Haischer, John Krzyszkowski, Stuart Roche, Kristof Kipp

Exercise Science Faculty Research and Publications

Maximal strength is important for the performance of dynamic athletic activities, such as countermovement jumps (CMJ). Although measures of maximal strength appear related to discrete CMJ variables, such as peak ground reaction forces (GRF) and center-of-mass (COM) velocity, knowledge about the association between strength and the time series patterns during CMJ will help characterize changes that can be expected in dynamic movement with changes in maximal strength. Purpose: To investigate the associations between maximal strength and GRF and COM velocity patterns during CMJ. Methods: Nineteen female college lacrosse players performed 3 maximal-effort CMJs and isometric midthigh pull. GRF …

Hip And Knee Joint Angle Patterns And Kicking Velocity In Female And Male Professional Soccer Players: A Principal Component Analysis Of Waveforms Approach, Archit Navandar, Kristof Kipp, Enrique Navarro

Exercise Science Faculty Research and Publications

This study used principal component analysis (PCA) of waveforms to extract movement patterns from hip and knee angle time-series data; and determined if the extracted movement patterns were predictors of ball velocity during a soccer kick. Twenty-three female and nineteen male professional soccer players performed maximal effort instep kicks while motion capture and post-impact ball velocities data were recorded. Three-dimensional hip and knee joint angle time-series data were calculated from the beginning of the kicking leg’s backswing phase until the end of the follow-through phase and entered into separate PCAs for females and males. Three principal components (PC) (i.e., movement …

Head Impact Exposure In Youth And Collegiate American Football, Grace B. Choi, Eric P. Smith, Stefan M. Duma, Steven Rowson, Eamon Campolettano, Mireille E. Kelley, Derek A. Jones, Joel D. Stitzel, Jillian E. Urban, Amaris Genemaras, Jonathan G. Beckwith, Richard M. Greenwald, Arthur C. Maerlender, Joseph J. Crisco

Center for Brain, Biology, and Behavior: Faculty and Staff Publications

The relationship between head impact and subsequent brain injury for American football players is not well defined, especially for youth. The objective of this study is to quantify and assess Head Impact Exposure (HIE) metrics among youth and collegiate football players. This multiseason study enrolled 639 unique athletes (354 collegiate; 285 youth, ages 9–14), recording 476,209 head impacts (367,337 collegiate; 108,872 youth) over 971 sessions (480 collegiate; 491 youth). Youth players experienced 43 and 65% fewer impacts per competition and practice, respectively, and lower impact magnitudes compared to collegiate players (95th percentile peak linear acceleration (PLA, g) competition: 45.6 vs …

Influence Of The Bar Position On Joint-Level Biomechanics During Isometric Pulling Exercises, Nayun Ahn, Hoon Kim, John Krzyszkowski, Stuart Roche, Kristof Kipp

Exercise Science Faculty Research and Publications

The purpose of this study was to investigate the influence of the bar position on ankle, knee, and hip net joint moments (NJMs), relative muscular effort (RME), and vertical ground reaction forces (GRFs) during isometric pulling exercises, such as the isometric midthigh pull. Eight female lacrosse athletes performed maximal effort isometric pulls at 3 different bar positions (low: above patella, mid: midthigh, and high: crease of hip) while motion capture and GRF data were recorded. Net joint moments were calculated with inverse dynamics. Relative muscle effort was defined as the ratio between the inverse dynamics NJMs and the maximum theoretical …

Prediction Of Throwing Distance In The Men’S And Women’S Javelin Final At The 2017 Iaaf World Championships, John Krzyszkowski, Kristof Kipp

Exercise Science Faculty Research and Publications

The purpose of this study was to use regularised regression models to identify the most important biomechanical predictors of throwing distance in elite male (M) and female (F) javelin throwers at the 2017 IAAF world championships. Biomechanical data from 13 male and 12 female javelin throwers who competed at the 2017 IAAF world championships were obtained from an official scientific IAAF report. Regularised regression models were used to investigate the associations between throwing distance and release parameters, whole-body kinematic and joint-level kinematic data. The regularised regression models identified two biomechanical predictors of throwing distances in both M and F javelin …

Line Hops And Side Hold Rotation Tests Load Both Anterior And Posterior Shoulder: A Biomechanical Study, Margie K. Olds, Nicole Lemaster, Kelsey Picha, Cody Walker, Nicholas R. Heebner, Timothy L. Uhl

Sports Medicine Research Institute Faculty Publications

Background: Clinical tests should replicate the stressful positions encountered during sport participation. Evaluating the kinetic and electromyographical demands of clinical tests enables clinicians to choose appropriate tests for specific sports.

Purpose: To describe the shoulder forces and muscle activation levels during closed chain functional tests of Line Hops (LH) and Side Hold Rotation (SHR).

Study Design: Descriptive biomechanical study.

Methods: Ten asymptomatic participants were examined in a university laboratory. Two functional tests were evaluated using three-dimensional video analysis and electromyography to measure shoulder forces, moments, and muscular activity levels.

Results: SHR produced a peak average posterior translation force of 4.84 …

The Application Of Biomechanical Technology In Sports, Timothy Leckrone

Senior Honors Theses

Technology in biomechanics encompasses eight major categories: artificial optical devices, anthropometry, timing devices, electrogoniometry, electromyography, dynamometry, inertial tracking systems, and modeling and simulation. As technology improves and becomes more accessible to the general population, it becomes easier to implement biomechanical technology into sports. For each area of focus, biomechanical technology has numerous points of current application or potential application. This application has benefit in injury prevention, technique improvement, rule enforcement, performance optimization, overall health and condition analysis, sports timing, and product development and testing. This thesis examines each area in turn as well as the various tools implemented in order …

Hip Moment And Knee Power Eccentric Utilisation Ratios Determine Lower-Extremity Stretch-Shortening Cycle Performance, Kristof Kipp, John Krzyszkowski, Jordi Heeneman

Exercise Science Faculty Research and Publications

The eccentric utilisation ratio (EUR) is calculated as the ratio between countermovement jump (CMJ) and squat jump (SJ) heights, and is an indicator of lower-extremity stretch-shortening cycle (SSC) performance in athletes. Joint-based EUR can also be calculated but have never been reported. The purpose of this study was to investigate whether jump height-based (JH-based) EUR can be predicted by joint-specific EUR. Nine NCAA Division I college athletes (age: 21 ± 1 year, height: 1.75 ± 0.15 m, mass: 71 ± 20 kg) performed three SJ and CMJ. During all jumps, kinematic and kinetic data were obtained and used to calculate …

Survey Of Barbell Trajectory And Kinematics Of The Snatch Lift From The 2015 World And 2017 Pan-American Weightlifting Championships, Aaron Cunanan, W. G. Hornsby, Mark A. South, Kristina P. Ushakova, Satoshi Mizuguchi, Kimitake Sato, Kyle C. Pierce, Michael H. Stone

ETSU Faculty Works

Analysis of elite performances is important to elucidate the characteristics of effective weightlifting technique contributing to the highest level of achievement. The general technique of the weightlifting movements is well established. However, it is also apparent that weightlifting technique can differ based on athlete characteristics. Thus, existing technical models may not accurately reflect current technique of top performers or be applied generically to athletes of different skill, size, sex, or ability. Therefore, the purpose of this descriptive study was to update the scientific knowledge of snatch technique of top international weightlifters. This study used video analysis to determine barbell trajectory …

Risk Factors Associated With Low Back Pain In Golfers: A Systematic Review And Meta-Analysis, Jo Armour Smith, Andrew Hawkins, Marybeth Grant-Beuttler, Richard Beuttler, Szu-Ping Lee

Physical Therapy Faculty Articles and Research

Context:

Low back pain is common in golfers. The risk factors for golf-related low back pain are unclear but may include individual demographic, anthropometric, and practice factors as well as movement characteristics of the golf swing.

Objective:

The aims of this systematic review were to summarize and synthesize evidence for factors associated with low back pain in recreational and professional golfers.

Data Sources:

A systematic literature search was conducted using the PubMed, CINAHL, and SPORTDiscus electronic databases through September 2017.

Study Selection:

Studies were included if they quantified demographic, anthropometric, biomechanical, or practice variables in individuals with and without golf-related …

The Effect Of Tackling Training On Head Accelerations In Youth American Football, Eric Schussler, Richard J. Jagacinski, Susan E. White, Ajit M. Chaudhari, John A. Buford, James A. Onate

Rehabilitation Sciences Faculty Publications

Background: Many organizations have introduced frameworks to reduce the incidence of football related concussions through proper equipment fitting, coach education, and alteration of tackling technique.

Purpose: The purpose of this study was to examine the effects of training in a vertical, head up tackling style on the number of head accelerations experienced while tackling in a controlled laboratory situation. The authors hypothesized that training in a head up tackling technique would reduce the severity of head acceleration experienced by participants.

Design: Controlled Laboratory Study.

Methods: Twenty-four participants (11.5 ± 0.6 years old, 60.5 ± 2.2 in, 110 ± 18.4 lbs.) …

Reliability And Validity Of A Biomechanically Based Analysis Method For The Tennis Serve, Natalie L. Myers, W. Ben Kibler, Leah Lamborn, Belinda J. Smith, Tony English, Cale A. Jacobs, Timothy L. Uhl

Physical Therapy Faculty Publications

Background: An observational tennis serve analysis (OTSA) tool was developed using previously established body positions from three-dimensional kinematic motion analysis studies. These positions, defined as nodes, have been associated with efficient force production and minimal joint loading. However, the tool has yet to be examined scientifically.

Purpose: The primary purpose of this investigation was to determine the inter-observer reliability for each node between two health care professionals (HCPs) that developed the OTSA, and secondarily to investigate the validity of the OTSA.

Methods: Two separate studies were performed to meet these objectives. An inter-observer reliability study preceded the …

Kinematics Of The Lower Extremities During Fundamental Martial Arts Tricking Techniques, Kevin P. Grassie

Honors Scholar Theses

Martial Arts Tricking (MAT) is a relatively new sport that combines martial arts, gymnastics, acrobatics, and breakdancing for the purposes of creating aesthetic and impressive combinations of kicks, flips and twists. It has been growing exponentially through social media and the overall athletic and entertainment communities. The sport is very unique in that the movements, with their blended influences, provide novel ways for athletes to generate and utilize their momentum in a creative way. The results often include off-axis flips and twists, single-leg landings, and complicated yet fluid techniques that easily chain together.

Due to the sport only being a …

The Effect Of Dimple Error On The Horizontal Launch Angle And Side Spin Of The Golf Ball During Putting, Ashley K. Richardson, Andrew C.S. Mitchell, Gerwyn Hughes

Kinesiology (Formerly Exercise and Sport Science)

This study aimed to examine the effect of the impact point on the golf ball on the horizontal launch angle and side spin during putting with a mechanical putting arm and human participants. Putts of 3.2 m were completed with a mechanical putting arm (four putter-ball combinations, total of 160 trials). The centre of the dimple pattern (centroid) was located and the following variables were measured; distance and angle of the impact point from the centroid and surface area of the impact zone. Multiple regression analysis was conducted to identify whether impact variables had significant associations with ball roll variables; …

A Biomechanical Comparison Of Successful And Unsuccessful Power Clean Attempts, Kristof Kipp, Carolyn M. Meinerz

Exercise Science Faculty Research and Publications

Although the power clean is an almost ubiquitous exercise in the strength and conditioning setting, relatively little is known about the biomechanics of successful and unsuccessful power clean lift attempts. The purpose of this study was to determine biomechanical differences between successful and unsuccessful power clean lift attempts in male collegiate athletes. Fifteen male lacrosse players (Age: 20.1 ± 1.2; Height: 1.78 ± 0.07 m; Body mass: 80.4 ± 8.1 kg; Relative one-repetition maximum power clean: 1.25 ± 0.13 kg/kg) were videotaped during a lifting session that required the completion of maximal effort power cleans to establish a one-repetition maximum. …

The Ability Of The Landing Error Scoring System To Detect Changes In Landing Mechanics: A Critically Appraised Topic, Claire E. Pointer, Tyler D. Reems, Emily M. Hartley, Johanna M. Hoch

Rehabilitation Sciences Faculty Publications

Clinical Question: Is there evidence to suggest that the Landing Error Scoring System (LESS) is able to detect functional changes in landing mechanics in healthy individuals after participation in an injury prevention program (IPP)? Clinical Bottom Line: In a healthy, physically active population, there is strong evidence to support the use of the LESS as an outcome measure for changes in landing mechanics after the implementation of IPPs. Clinicians should consider the LESS as an evaluative tool for measuring the efficacy of IPPs in clinical practice.

Muscle-Specific Effective Mechanical Advantage And Joint Impulse In Weightlifting, Kristof Kipp, Chad Harris

Exercise Science Faculty Research and Publications

Lifting greater loads during weightlifting exercises may theoretically be achieved through increasing the magnitudes of net joint impulses or manipulating the joints’ effective mechanical advantage (EMA). The purpose of this study was to investigate muscle-specific EMA and joint impulse as well as impulse-momentum characteristics of the lifter-barbell system across a range of external loads during the execution of the clean. Collegiate-level weightlifters performed submaximal cleans at 65, 75, and 85% of their 1-repetition maximum (1-RM) while data from a motion analysis system and a force plate were used to calculate lifter-barbell system impulse and velocity, as well as net extensor …

Mechanical Demands Of The Hang Power Clean And Jump Shrug: A Joint-Level Perspective, Kristof Kipp, Philip Malloy, Jordan Smith, Matthew D. Giordanelli, Michael T. Kiely, Christopher Geiser, Timothy J. Suchomel

Exercise Science Faculty Research and Publications

The purpose of this study was to investigate the joint- and load-dependent changes in the mechanical demands of the lower extremity joints during the hang power clean (HPC) and the jump shrug (JS). Fifteen male lacrosse players were recruited from an NCAA DI team, and completed three sets of the HPC and JS at 30%, 50%, and 70% of their HPC 1-Repetition Maximum (1-RM HPC) in a counterbalanced and randomized order. Motion analysis and force plate technology were used to calculate the positive work, propulsive phase duration, and peak concentric power at the hip, knee, and ankle joints. Separate three-way …

Biomechanical Investigation Of Elite Place-Kicking, Chase M. Pfeifer

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Many studies aim to understand the fundamentals of kicking commonly displayed by soccer players [4,6,10,16,17,18,24,25,28,29,30,34,36,38,40]. Of those studies, most are limited to a two-dimensional (2D) analysis using high-speed cameras for position tracking or utilizing electromyography to observe the activity of select muscles [4,6,18,25,29,36]. The few studies that investigate kicking using a three-dimensional (3D) model are limited in their position tracking capabilities and focus mainly on joint flexion potentials and foot speed.

This dissertation is a comprehensive biomechanical analysis (kinematic and EMG) of the field-goal place-kicking techniques of four elite kickers in American football. Data were compared and contrasted with ball …

Delivery And Pitch Type Alter Ground Reaction Forces In Baseball Pitching, Garrett Kass

Featured Research

Ground reaction forces (GRFs) exerted on a pitcher in reaction to the push of their legs against the ground create torques about the center-of-mass (CM) and generate the angular momentum necessary to rotate the body, including the segments of the throwing arm. Thus examination of GRFs provides insight into the causal mechanisms responsible for segmental rotation in baseball pitching. PURPOSE: To determine the effects of delivery [wind-up (WU) vs. stretch (ST)] and pitch type [fastball (FB) vs. change-up (CU)] on GRFs in pitching. METHODS: Eight collegiate baseball pitchers (4 right-handed and 4 left-handed) provided voluntary informed consent and threw maximal …

Correlations Between Internal And External Power Outputs During Weightlifting Exercise, Kristof Kipp, Chad Harris, Michelle B. Sabick

Exercise Science Faculty Research and Publications

Identifying loads that maximize mechanical power is important because training at such loads may optimize gains in dynamic athletic performance. The purpose of this study was to examine correlations between measures of external mechanical power output and internal mechanical joint power output across different loads during a weightlifting exercise. Ten subjects performed 3 sets of the clean exercise at 65, 75, and 85% of 1 repetition maximum (1RM). Peak external mechanical power output was calculated with 4 commonly used methods, whereas an inverse dynamics approach was used to calculate peak internal mechanical power output for the hip, knee, and ankle …

A Feedback Inclusive Neuromuscular Training Program Alters Frontal Plane Kinematics, Eric K. Greska, Nelson Cortes, Bonnie L. Van Lunen, James A. Oñate

Rehabilitation Sciences Faculty Publications

-Anterior cruciate ligament (ACL) neuromuscular training programs have demonstrated beneficial effects in reducing ACL injuries, yet further evaluation of their effects on biomechanical measures across a sports team season is required to elucidate the specific factors that are modifiable. The purpose of this study was to evaluate the effects of a 10-week off-season neuromuscular training program on lower extremity kinematics. Twelve Division I female soccer players (age: 19.2 ± 0.8 years, height: 1.67 ± 0.1 m, weight: 60.2 ± 6.5 kg) performed unanticipated dynamic trials of a running stop-jump task pretraining and posttraining. Data collection was performed using an 8-camera …

Weightlifting Performance Is Related To Kinematic And Kinetic Patterns Of The Hip And Knee Joints, Kristof Kipp, Josh Redden, Michelle B. Sabick, Chad Harris

Exercise Science Faculty Research and Publications

The purpose of this study was to investigate the correlations between biomechanical outcome measures and weightlifting performance. Joint kinematics and kinetics of the hip, knee, and ankle were calculated while 10 subjects performed a clean at 85% of 1 repetition maximum (1RM). Kinematic and kinetic time-series patterns were extracted with principal components analysis. Discrete scores for each time-series pattern were calculated and used to determine how each pattern was related to body mass–normalized 1RM. Two hip kinematic and 2 knee kinetic patterns were significantly correlated with relative 1RM. The kinematic patterns captured hip and trunk motions during the first pull …

Center Of Pressure Excursion During The Golf Putting Stroke In Low, Mid And High Handicap Golfers, Ashley K. Richardson, Gerwyn Hughes, Andrew C.S. Mitchell

Kinesiology (Formerly Exercise and Sport Science)

Golf handicap is significantly correlated to putting performance with low handicap golfers (LH) demonstrating increased putting accuracy compared with high handicap golfers (HH). Smaller center of pressure excursion (CPE) during putting has been demonstrated by LH golfers, suggesting balance is important during successful putts. The aim of this study was to examine CPE in low, mid and high handicap golfers about the mediolateral axis (ML) and anteriorposterior axis (AP). Nineteen subjects participated in the study; subjects were split into LH, mid handicap and HH groups. Subjects completed five successful 2.5m putts, standing on an RS FootScan. The LH group demonstrated …

Swing And Launch Parameters In Approach-Iron Shots Hit With Varying Height And Trajectory In Golf, Samuel J. Robertson, Angus Burnett

Research outputs 2012

The first aim of this study was to determine whether relationships existed between variability of swing and launch parameters and variability in shot outcome for straight golf shots. The second aim was to determine whether differences existed for swing and launch parameters in shots intentionally played with varying height and trajectory. Elite (n=20) and high-level amateur (n=22) golfers hit; 1) five straight shots of normal height and 2) nine shots of differing height (low, normal, high) and trajectory (straight, draw, fade). Variability of club attack angle, face angle and ball spin axis was significantly associated (p