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Full-Text Articles in Medicine and Health Sciences
Muscle-Specific Contributions To Lower Extremity Net Joint Moments While Squatting With Different External Loads, Kristof Kipp, Hoon Kim, William I. Wolf
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
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
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 …
Influence Of The Bar Position On Joint-Level Biomechanics During Isometric Pulling Exercises, Nayun Ahn, Hoon Kim, John Krzyszkowski, Stuart Roche, Kristof Kipp
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
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 …
Hip Moment And Knee Power Eccentric Utilisation Ratios Determine Lower-Extremity Stretch-Shortening Cycle Performance, Kristof Kipp, John Krzyszkowski, Jordi Heeneman
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 …
A Biomechanical Comparison Of Successful And Unsuccessful Power Clean Attempts, Kristof Kipp, Carolyn M. Meinerz
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. …
Muscle-Specific Effective Mechanical Advantage And Joint Impulse In Weightlifting, Kristof Kipp, Chad Harris
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
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 …
Correlations Between Internal And External Power Outputs During Weightlifting Exercise, Kristof Kipp, Chad Harris, Michelle B. Sabick
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 …
Weightlifting Performance Is Related To Kinematic And Kinetic Patterns Of The Hip And Knee Joints, Kristof Kipp, Josh Redden, Michelle B. Sabick, Chad Harris
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 …