The Biomechanics of a Free Throw Shot BY: VINAY RAO BIOL438 Professor rome 21 April 2011

Free Throw Basics Definition – unopposed attempts to score points from a restricted area on the court (foul line), and are generally awarded after a foul on the shooter by the opposing team. Four Basic Steps Knee Bed Ball Elevation Ball Release Wrist Pronation Shooting Mechanics: BEEF Balance Elbow Elevation Follow Through

Free Throw: Muscles Recruited Triceps Triceps brachii muscle: long head, lateral head, and medial head Work to extend the arm at the elbow Biceps Double-headed muscle located on the front of the upper arm. Flexes the arm at the elbow Deltoids Responsible for arm abduction, movement observed in non-shooting arm, mainly utilized when pushing ball away from the body

Muscles Recruited Cont. Pecs Fan-shaped muscles covered that covers the upper portion of the chest and overlays the thin pectoralis minor. Prime mover of arm flexion and assist the anterior deltoid in ball push Wrist Flexors Includes the flexor digitorum superficials and flexor digitorum profundus. Act to flex the wrist and fingers – very important in follow through Quadriceps Allows “soft knees” through contraction of the quadricep muscles. Calves Comprised of gastrocnemeus and the soleus muscles – work to flex the foot. Provides necessary motion for Kinetic Chain

Review of Literature Subjective assessments of the product elements of angle and velocity of projection are abudent Numerous understandings: some say high angle, some say low, some say 45 degrees particularly Stability often cited as a factor of free throw accuracy Release point: high or low release point?

Question Subject: To test what biomechanical factors play a role in the success of a free throw shot Hypothesis: Certain variables matter over others: i.e. velocity of ball upon release negligible, whereas balance and ball release are necessary.

Experimental Protocol Subjects – Two skill levels will be observed, one of high skill and one of low skill. Variables Accuracy – confirmed skill level based on 20 free throw test Height of Release Ratio – height of the ball upon release divided by height of the subject Center of Gravity Ratio – distance from frontal aspect to center of gravity divided by base support length Trunk Inclination – degrees of leaning either forward or backward Velocity of Project – based on loggerpro analysis

The Competitors Kathlyn Herrick (low skill) Zack Rosen (high skill) Credentials: Math Major Penn Relays 3 year participant…? Zack Rosen (high skill) Credentials: Guard on Penn Varsity Basketball Team 415 Career Assists (4th all time at Penn), 1,121 points (28th all time at Penn) 2009-2010 First Team All Ivy (unanimous)

Kathlyn Herrick: Slow Motion Shot

Zack Rosen: Slow Motion Shot

Results Kathlyn Herrick Zack Rosen Free Throw Percentage 25% %70 Height of Release Ratio 1.077 1.269 Center of Gravity 0.613 0.4 Trunk Inclination 7 degrees 2 degrees Resultant Velocity 7.65 meters per seconds 7.96 meters per seconds

Discussion Accuracy: significant difference in free throw percentage illustrates varying skill level Height Release Ratio: observed significant difference between release ratios – Rosen’s ball release was ~18% larger than Herrick’s. Center of Gravity Ratio: the lower value of Rosen signified more stability whereas the higher value of Herrick’s (quite great) contributes may contribute to inaccuracy Trunk Inclination: seemed to be negligible Velocity of Projection: revealed to be not significant

Conclusions Higher Heights of Release is related to Higher Skill Level Greater Stability is related to Higher Skill Level Velocity Projection is not related to Skill Level

Supplemental Measurements KE of the basketball: Low Skill KE = 1/2mv2 = (1/2)(.624 kg)(7.65 m/s)^2 = 18.26 J High Skill KE = 1/2mv2 = (1/2)(.624 kg)(7.96 m/s)^2 = 19.77 J Momentum of the basketball: Low Skill p = mv = (.624 kg)(7.65 m/s) = 4.77 kg*m/s High Skill p = mv = (.624 kg)(7.96 m/s) = 4.96 kg*m/s Similarity of KE and Momentum calculations highlight the potential irrelevance that velocity of basketball release has on free throw shot effectiveness

Further Directions Increase the number of N to further prove statistically the importance of this data analysis Perhaps test angle projection to see whether, like velocity, is somewhat independent on skill

References Hudson, Jackie. A Biomechanical Analysis by Skill Level of Free Throw Shooting in Basketball. Biomechanics of Sports. 1982; 95-102. http://www.livestrong.com/article/104294-muscles-used-shooting-basketball/ http://www.scribd.com/doc/26028188/Human-Movement-Analysis-Basketball-Set-Shot