Biomechanics of Sport Applications PDF

1   Anatomical Planes of the Human Body The body is erect, the arms are down at the sides, and the palms face forward. The sagittal plane slices the body into left‐right sections. The frontal plane slices the body...

1   Anatomical Planes of the Human Body The body is erect, the arms are down at the sides, and the palms face forward. The sagittal plane slices the body into left‐right sections. The frontal plane slices the body into front‐back sections. The transverse plane slices the body into upper‐lower sections. Fig. 2.9. Haff et al. 2016. Essentials of Strength… Human Kinetics 2   Specificity is a major consideration when one is designing an exercise program to improve performance in a particular sport activity.  The sport movement must be analyzed qualitatively or quantitatively to determine the specific joint movements that contribute to the whole‐body movement.  Exercises that use similar joint movements are then emphasized in the resistance training program. 3 4 Fig. 2.10. Haff et al. 2016. Essentials of Strength… Human Kinetics  Arrangement of Muscle Fibers Muscle Length Joint Angle Muscle Contraction Velocity Joint Angular Velocity Strength‐to‐Mass Ratio Body Size 5   Basic Definitions strength: The capacity to exert force at a given speed. force = mass * acceleration work = force * distance Or, work = torque * angular displacement power = force * velocity Or, power = work / time The rate at which the repetitions are performed determines the power output. Negative work refers to work performed on, rather than by, a muscle (i.e. eccentric). 6   Biomechanical Factors in Human Strength Muscle Cross‐Sectional Area (CSA) The force a muscle can exert is related to its cross‐sectional area rather than to its volume. The greater the CSA, the more sarcomeres can be stacked parallel or on top of each other. – Recall that force is determined by the number of crossbridges that can be formed. Equal CSA means = strength – Equal CSA, but smaller volume → more power (gymnasts) 7   Arrangement of Muscle Fibers Variation exists in the arrangement and alignment of sarcomeres in relation to the long axis of the muscle.  pennate muscle: A muscle with fibers that align obliquely with the tendon, creating a featherlike arrangement.  angle of pennation: The angle between the muscle fibers and an imaginary line between the muscle’s origin and insertion; 0° corresponds to no pennation. 8 9 Fig. 2.11. Haff et al. 2016. Essentials of Strength… Human Kinetics   Figure 2.11 (previous slide) Muscles with greater pennation have more sarcomeres in parallel and fewer sarcomeres in series. More pennation = greater ability to generate force, but lower shortening velocity Pennation can also be disadvantageous for eccentric and isometric muscle actions. 10   Haff & Triplett. Essentials of Strength Training & Conditioning, 4th edition. Human Kinetics, 2016.  Kenney, Wilmore, Costill. Physiology of Sport & Exercise, 6th edition. Human Kinetics, 2015.  McCardle, Katch, Katch. Exercise Physiology: Nutrition, Energy, and Human Performance, 8th edition. Wolters Kluwer Health, 2014. 11