force – The Sport Journal

Kinetics and Kinematics of Commonly Used Quarterback Throwing Approaches – A Case Study

Authors: Dimitrije Cabarkapa ¹, Andrew C. Fry ¹, and Eric M. Mosier ²

¹Jayhawk Athletic Performance Laboratory, University of Kansas, Lawrence, KS, USA
² Northwest Missouri State University, Maryville, MO, USA

Corresponding Author:
Dimitrije Cabarkapa, MS, CSCS, NSCA-CPT, USAW
Jayhawk Athletic Performance Laboratory
University of Kansas
1301 Sunnyside Avenue, Lawrence, KS 66047
dcabarkapa@ku.edu
785-864-5552

Kinetics and Kinematics of Commonly Used Quarterback Throwing Approaches – A Case Study

ABSTRACT

The purpose of this study was to analyze kinetic and kinematic components for six of the most commonly used quarterback drop throwing patterns and determine how further performance improvements can be made. One male right-handed quarterback athlete volunteered to perform multiple repetitions of the six most commonly used right-handed drop throwing approaches: standing still and throw (SST), one-step left-right (1SLR), one-step right-left (1SRL), three-step straight ahead (3SSA), three-step shot gun (3SSG), and five-step throw (5ST). Kinetic data was collected with a uniaxial force plate while kinematic data was captured with high definition cameras. One-way analysis of variance was used to determine the differences between the six throwing approaches for the kinetic and kinematic variables examined in this study. The statistical significance level was set a priori to p<0.05. Peak right leg force demonstrated significantly lower magnitudes for 1SRL when compared to 1SLR, 3SSG, and 5ST. Peak left leg force for the 3SSA was lower when compared to 1SRL and 1SLR. Throw arm elbow angle was greater for SST when compared to all other throwing approaches. No difference was observed for ball speed, non-throw arm elbow angle, front leg knee angle, and back leg knee angle between any of the examined throwing approaches. Our results indicate that the majority of ground reaction force production required for an optimal quarterback throwing motion comes from the rear leg, and the magnitudes may reach three times bodyweight forces. Ground reaction forces may be enhanced with a greater number of drop steps, which may ultimately increase quarterback throwing distance. Greater throwing arm elbow extension may be induced as biomechanical adjustment due to lack of force production caused by the inability of the quarterback to take a greater number of drop steps.

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U.S. Sports Academy2020-09-08T10:15:00-05:00December 11th, 2020|Sports Health & Fitness|Comments Off

Validity of 3-D Markerless Motion Capture System for Assessing Basketball Dunk Kinetics – A Case Study

Authors: Dimitrije Cabarkapa¹, Andrew C. Fry¹ and Eric M. Mosier²

Jayhawk Athletic Performance Laboratory, University of Kansas, Lawrence, KS
Northwest Missouri State University, Maryville, MO

Corresponding Author:
Dimitrije Cabarkapa, MS, CSCS, NSCA-CPT, USAW
1301 Sunnyside Avenue, Lawrence, KS 66045
University of Kansas
E-mail: dcabarkapa@ku.edu
Phone: +1 (785) 551-3882

Validity of 3-D Markerless Motion Capture System for Assessing Basketball Dunk Kinetics – A Case Study

ABSTRACT

Basketball is one of the most popular international sports, but the current sport science literature does not directly address on-court performance such as force and power during a game. This case study examined the accuracy of a three-dimensional markerless motion capture system (3-D MCS) for determining the biomechanical characteristics of the basketball dunk. A former collegiate (NCAA Division-I) basketball player (age=26 yrs, height=2.08 m, weight=111.4 kg) performed 30 maximum effort dunks utilizing a two-hands, no-step, two-leg jumping approach. A uni-axial force plate (FP) positioned under a regulation basket sampled data at 1000 Hz. Additionally, a 3-D MCS composed of eight cameras placed 3.7 m high surrounding the recording area collected data at 50 Hz, from which ground reaction forces were derived using inverse dynamics. The dunks were analyzed by both systems for peak force and peak power. Peak force (X±SD) was similar (p<0.05) for both systems (FP= 2963.9±92.1 N, 3-D MCS= 3353.2±255.9 N), as was peak power (FP= 5943±323, 3-D MCS= 5931±700 W). Bland-Altman plots with 95% confidence intervals for both force and power indicated all measurements made with the 3-D MCS accurately assessed peak force and peak power during a basketball dunk as performed in the current study. These data provide strength and conditioning professionals with a better understanding of the magnitude of forces and powers that athletes experience during a basketball game, as well as validate use of a novel technology to monitor athletes’ progress and optimize overall athletic performance.

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U.S. Sports Academy2020-05-06T09:16:36-05:00June 19th, 2020|Research, Sports Health & Fitness|Comments Off

Position-Specific Task, Strength, and Performance Comparisons between NCAA Division I Offensive and Defensive Linemen

Submitted by Garrett M. Hester, Bert H. Jacobson, Ty B. Palmer, Doug B. Smith and Matthew S. O’Brien

ABSTRACT

The ultimate goal of strength and conditioning practitioners is to improve performance on the field. To date, little data exist that provides evidence of strong relationships between selected exercises and sport-specific tasks. PURPOSE: The purpose of this study was to compare the performance of a position-specific task on the MAXX Football Sled Device (MX) between NCAA Division I offensive (OL) and defensive linemen (DL) and to determine the associations among selected strength and performance variables with results on the MX. METHODS: Offensive (n = 12) and defensive linemen (n = 14) (age 20.11 ±1.49 yrs) performed 10 “fire-off-and-drive” repetitions on the MX from a three-point stance. Data relative to force (N) and movement time (MT) was collected for each repetition on the MX. The duration between each repetition was automatically randomized between 6 to 10 sec. Strength and performance data including 1 RM of the squat, bench press, and power clean, along with vertical jump, 10 yd sprint, 40 yd sprint, and body fat percentage were gathered as part of seasonal standard assessment. RESULTS: Results yielded significant differences in body weight, sprint performances, 1 RM squat, and a near significant difference in MT (p = 0.052) between OL and DL. With respect to performance on the MX, there were no significant associations among selected strength and performance measures and MT on the MX. Although insignificant, force on the MX was found to have moderate associations with the 10 yd sprint (r = .457) and 1 RM power clean (r = .463). CONCLUSIONS: Primarily, these results point out that little carry over exists between the standard exercises performed and the task performed on the MX. Further research for the purpose of finding exercises that correlate with a position-specific task in these athletes is warranted. APPLICATION IN SPORT: A priority among practitioners is to remain cognizant of the positional role differences and distinct physical characteristics between OL and DL. The OL and DL positions should be categorized separately so that specific evaluative and training needs can be met for each position.
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U.S. Sports Academy2014-05-07T14:04:41-05:00April 11th, 2014|Contemporary Sports Issues, Sports Exercise Science|Comments Off