Education Commons^™

The Effects Of A Heel Lift On Squat Biomechanics, Lexy Clark, Miranda Moeslein, Donovyn Murray, Jared W. Coburn, Kevin Choe

International Journal of Exercise Science: Conference Proceedings

The barbell squat is an effective exercise for improving lower extremity function. During the descent of a squat, the hip and knee joints flex while the ankle joint dorsiflexes. The hip and knee joints then extend and the ankle joint plantarflexes when standing up. During the squat, some athletes use shoes with an elevated heel or other means of heel elevation to achieve lower squat depth. Research has suggested that use of heel elevation may improve range of motion (ROM) of the lower extremity joints and improve stability of the movement during deep squats, especially with an external load. PURPOSE …

Unilateral Load Carriage In Golf Increases Frontal Plane Moment Demand At The Knee, Guanrong Cai, Jordan Cannon, Yunsheng Zou, George Salem

International Journal of Exercise Science: Conference Proceedings

Golf equipment transportation (GET) is a regular task in the sport of golf, a popular activity with more than 66 million participants globally. Unilateral GET is commonly practiced by junior and collegiate golfers, and professional caddies, who incur large walking distances daily, especially during competition. Therefore, the influence of GET on knee mechanics during gait has important implications for performance and injury risks. Furthermore, frontal-plane lower extremity (LE) demands including knee abductor moment during activities may alter knee mechanics and contribute to pain and progression of osteoarthritis (OA). Purpose: To compare the frontal-plane knee moments of two different GET methods …

The Two-Dimensional Relationship Between Ground Reaction Force Vector And Knee Axis Of Rotation Reflect Knee Loading Deficits During Squatting Post-Aclr, Jiaqi Wang, Susan Sigward

International Journal of Exercise Science: Conference Proceedings

PURPOSE

Individuals post-anterior cruciate ligament reconstruction (ACLr) perform reduced knee extensor moments (KEM) during squats by shifting weight to the non-surgical (NSx) limb ¹ or by shifting demands from the knee to hip ^1,2. These compensations occur without observable differences in joint angles by small adjustments in the center of pressure (COP). This makes them difficult to detect and may contribute to their persistence. Differences between limbs in COP position suggest that individuals adjust the relationship of the ground reaction force vector (GRFv) relative to the joint center to redistribute the loading demands in the surgical limb ³. …

The Impact Of Squat Velocity On Force, Power, And Muscle Activity, Kyle D. Puccini, James Baldonado, Bonnie Yee, Christie R. O'Hara

International Journal of Exercise Science: Conference Proceedings

The squat is a thoroughly examined movement pattern and commonly used in sport performance training protocols, rehabilitation programs, and recreational exercise. Previous research measuring absolute strength has shown hamstring muscle activity in a six-repetition max barbell back squats. PURPOSE: The purpose of this study is to examine the effects of varying squat velocities (25, 50, 75 deg/s) on force, power, and the activation of the quadricep and hamstring muscles. Using a single-blind randomized research design, we hypothesized that hamstring muscle activity will increase at faster squat velocities. Our secondary hypothesis is that peak power will occur at 50 deg/s and …

Laboratory Measurements Of Division 1 College Baseball Players To Predict Field Base Performance, Sebastian Ortiz, Lyric Richardson, Emma Bozarth, Amy Riera, Kase Pennartz, Micheal Luera

International Journal of Exercise Science: Conference Proceedings

Cross-sectional area (CSA) of skeletal muscle has been commonly used as a predictor of force production. Peak force (PF) production during maximal contractions of the lower body can be a primary indicator of an athlete’s potential to perform on the field. PURPOSE: The purpose of this study was to use CSA for the VL and RF and PF to predict 60-yard dash times. METHODS: Fifteen male athletes (20.64 yrs. ±1.54, 182.89 cm. ±5.74, 196.58 kg ±21.2.) participated in this investigation. Sixty-yard dash times were recorded from each athlete prior to laboratory testing. Skeletal muscle CSA were taken from the VL …

Monitoring Firing Behaviors Of Motor Unit Action Potentials During Low-Intensity Fatiguing Contractions, Dakota Harris, Lyric Richardson, Amy Riera, Emma Bozarth, Micheal Luera

International Journal of Exercise Science: Conference Proceedings

Motor Units (MU) are systematically activated from increasing size in accordance to the size principle. As muscle fatigue sets in, MU firing rate increases in response to sustaining whole-body force production during a low-loaded sustained contraction with respect to MU size and MU interspike intervals (ISI). PURPOSE: The purpose of this study is to compare the motor unit firing behaviors during low-force isometric fatiguing contractions. Methods: Following 3 MVCs, eight lower-body resistance trained males (23.38 ± 2.88 yrs.; 178.38 ± 7.85 cm; 86.10 ± 11.88 kg) performed 60 second submaximal (30% MVC) isometric ramp contraction of the knee extension …

Lower Extremity Muscle Activity When Walking On A Non-Motorized Treadmill, Carl P. Shaulis, Sam I. Anderson, Riley A. Barlage, Scott P. Mclean

International Journal of Exercise Science: Conference Proceedings

Effective interventions for increasing walking speed are important for improving health and quality of life in aging populations. Non-motorized treadmills (NMT) may enhance the ability to develop or improve motor control in gait by requiring the participant to produce and maintain speed as compared to use of a motorized treadmill (MT) which requires one to simply match speed. PURPOSE: The purpose of this project was to compare muscle activation patterns of lower extremity muscles between MT, NMT and overground (OG) walking. METHODS: Twenty healthy adults (24.4±7.2 yrs, 1.75±0.09 m, 75.4±13.1 kg) completed one trial of walking at each …

Cortical Activity Measured With Low-Intensity Fatiguing Contractions Of The Quadriceps Muscle Group, Emma D. Bozarth, Lyric D. Richardson, Amy E. Riera, Micheal J. Luera, Amber H. Bozer

International Journal of Exercise Science: Conference Proceedings

Modulation of force production required during exercise is regulated from various mechanisms in the central and peripheral nervous system. Fatigue is influenced by various mechanics that may hinder the ability to continuously sustain force production. The neural activation patterns of these systems can be recorded as electrical impulses using several non-invasive techniques. The ability to examine these during fatiguing exercise has provided further insight into activation patterns in the central nervous system (i.e., motor and pre-motor cortex) during sustained muscle contractions. Electroencephalography (EEG) has been recently utilized to examine changes associated with central fatigue, but limited advancements in technology for …

Effects Of Low-Intensity Fatigue On Motor Unit Firing Properties During Maximal Voluntary Isometric Contractions, Lyric Richardson, Amy Riera, Emma Bozarth, Micheal Luera

International Journal of Exercise Science: Conference Proceedings

Rehabilitation from injuries impairing the neuromuscular system is often difficult to quantify due to task specificity of the affected or immobilized limb or limbs. Often, exercise regimens with clinical practitioners are designed to progress motor performance to a capacity that reflects muscle force production to pre-injury capacity. Modulation of force production from these tasks are regulated from various mechanism in the central and peripheral nervous system. The neural activation of these systems can be recorded as electrical impulses using several non-invasive techniques. Recently, the ability to examine these during fatiguing exercise has provided further insight into activation patterns and firing …