Biomechanics of the Golf Swing Sean McGeown Courtney Costa Felicia Phillips MB Nia Charles-Stewart
The Golf Swing • The golf swing is a complex movement involving the whole body and is used to develop momentum that is transferred to the golf ball to propel it to its target. This movement pattern requires a coordinated sequence of muscle activity to efficiently transfer the power generated by the swing.
The Golf Swing • The primary objective of a golfer executing the full swing is to produce maximum distance, accuracy, control, and consistently in each golf shot. • All movements of the body must be made in a sequence, and at a pace which allows the golf club to be swung in a rhythmic motion in the simplest possible arc, and on a path that produces on-center hits and maximum club head speed without great effort.
Preparing for the Golf Swing • The purpose of the grip is to insure the hands and wrists work together to transfer the force generated by the body and leg actions during the swing to the ball. • Posture and balance are crucial. The sequence of movements rests upon the feet. This is related to power generation. • Weight should be evenly distributed over both feet.
Preparing for the Golf Swing • To maintain balance, center of gravity must be within and directly over the support base. • Knees must be slightly flexed. This allows: • Greater torso rotation. • Leg extensor muscles on stretch • Force absorption during the follow through
Preparing for the Golf Swing • Foot alignment allows proper rotation, weight transfer, and good balance. • Feet, hips, and shoulders should be parallel to the target line (Line from golf ball to the pin.) • Feet should be shoulder width apart, knees slightly flexed, back straight to enhance trunk rotation, and hips slightly rotated forward. • Hip rotation allows a more upright swing and the arms to swing through more freely.
Preparing for the Golf Swing • Left arm should be straight allowing increased speed and range of motion (Assuming right-handed golfer). • If the left arm bends this varies the radius therefore decreasing alignment with target line. • Right elbow slightly flexed, close to the body.
Execution of the Golf Swing • The swing occurs in two planes, the plane of the backswing and the plane of the downswing. • The swing evolves around 3 dimensions: • Vertical, up and down movement. Controlled by the hands. • Lateral, side to side movement. Influenced by the arms. • Rotary, movement around the body. Controlled by the pivot of the body (hips).
Take Away Phase • The purpose of the take away is to establish a perfectly balanced, powerful position at the top of the swing. • In the take away the hands and shoulders must start in one motion. • At top the shoulders are coiled, hands swung high, and arms extended.
Take Away Phase • The greatest acceleration is at the top of the take away. This is accomplished by shortening the radius (lever arm). • This is done by bending the right elbow during the take away. • The weight of the feet in the stance shifts laterally from the front to the rear foot. This increases the range of hip rotation.
Newton’s Third Law (Action –Reaction) • The stretch reflex principle – when the whole muscle is stretched, the spindles cause a reflex contraction of their host muscle. • During Take Away phase, allows greater range of motion and increases muscle stretch. • Resulting with the contractile force of the muscle increasing and facilitating the recoil of elastic tissue.
Starts from the time the club starts movement to the top of the back swing Active Muscles Upper Body/Trunk Subscapularis Upper Serratus Upper & Middle Trapezius Lower Body/Trunk Erector Spinae Abdominal Oblique Semimembranosus Long Head of Biceps Femoris Take Away/Backswing Phase
Starts at the top of the swing and ends when the club is horizontal to the ground Active Muscles Upper Body/Trunk Rhomboid Middle Trapezius Pectoralis Major Upper Serratus Lower Body/Trunk Vastus Lateralis Adductor Magnus Gluteus Maximus Forward Swing Phase
Starts from the horizontal club to the impact of the ball Active Muscles Upper Body/Trunk Pectoralis Major Levator Scapulae Upper Serratus Lower Body/Trunk Biceps Femoris Gluteus Maximus & Medius Vastus Lateralis Abdominal Oblique Acceleration Phase
The Acceleration Phase • Same plane as the take away and is reaction phase of Newton’s Action-Reaction Law. • Hands and arms move the club, swinging arms turns the shoulder. Forward swing started by turning hips, which unwinds the upper part of the body. • This is referred to as the summation of forces principle.
The Acceleration Phase • When the club head strikes the ball, the wrists straighten and with the force of the trunk and other body parts produce maximum hitting effort. • Wrists are a major factor in maintaining maximum club head velocity. • Uncocking the wrists early decelerates arm motion therefore decreasing angular motion of the swing. If done at appropriate moment is a crucial mechanical element of the swing.
Starts at impact to when the club is horizontal to the ground Active Muscles Upper Body/Trunk Pectoralis Major Infraspinatus Subscapularis Lower Body/Trunk Long Head of Biceps Femoris Vastus Lateralis Gluteus Medius Abdominal Oblique Early Follow Through Phase
The Early Follow-Through Phase • Also known as recovery phase, maximum effort subsides. • The right arm begins to rotate and right hand begins to climb over the left. • Golfer’s head, stationary throughout the full swing, is pulled up and rotated forward by turning trunk and the momentum of swing.
Starts when the club is horizontal to the ground and ends at the completion of the swing. Active Muscles Upper Body/Trunk Infraspinatus Pectoralis Major Subscapularis Upper and Lower Serratus Lower Body/Trunk Semimembranosus Vastus Lateralis Adductor Magnus Gluteus Medius Late Follow Through Phase
The Late Follow-Through Phase • Although maximum effort has subsided, its still important to accelerate through impact. • This reduces danger of decelerating at impact. • Decreases possibility of injury. • Increases accuracy.
The biceps is the agonist, and the triceps are the antagonist. Agonist and Antagonist Muscles
Stabilizers are at the shoulder joint, hip joint, feet, wrist, knee and elbows. The transverse abdominis acts as a lumbar spine stabilizer Stabilizer Muscles
In order to maximize the club-head velocity at ball impact, considerable GRF must be produced To increase GRF the legs should be pushed down on the ground Loading the back foot with weight during the backswing and transferring this weight to the front foot during the downswing and acceleration phases can achieve a greater club-head velocity at impact Ground Reaction Force
Balance, Body Center of Mass and the Base of Support • In order to increase stability during a golf shot, the feet should be shoulder-width apart with the line of gravity of the center of mass within the trunk over the base of support (feet) and the postural muscles in the pelvic and abdominal region active • Static balance is being able to maintain a balanced body position • Dynamic balance is the ability to transfer weight correctly in the swing
Torque and Lever Arms • The tendency of a force to cause rotation around a pivot point is called torque, where the magnitude of the torque is equal to the product of the force and the lever arm • The length of the arm-club lever at the point of impact will have a direct result on the velocity of the ball
Axis of Rotation During Back Swing Phase (Concentric Phase) • Consist of two axis of rotation at the elbow and shoulder joints. These two axis of rotation helps in shortening of the moment arm, helps decrease mass of inertia and radius of gyration to produce force needed for explosive swing.
Axis of Rotation cont… During Down Swing Phase (Eccentric Phase) • During this phase only one axis of rotation is present, which is the shoulder joint. • The final stage of a swing determines the momentum of the ball.
Role of the Shoulder • The golf swing if performed correctly, does not require extreme ranges of motion and therefore does not require large contributions from the deltoids bilaterally. • Deltoids remain mostly inactive during all phases of the swing • The rotator cuff provides stability in order to protect the glenohumeral complex during the take away and follow through phases.
Role of the Shoulder • During the take away phase the infraspinatus and supraspinatus act together to provide stability to the shoulder joint. • During the late follow through phase the rotator cuff muscles act together to rapidly decelerate the arms.
Shoulder Injuries Related to Golf • In amateur golfers, the shoulder is the fourth most commonly injured area of the body, third amongst professionals. • Shoulder impingement involving the supraspinatus tendon may occur bilaterally due to decreased shoulder flexibility and degeneration of articular cartilage. • Subacromial tissues can be impinged due to the nature of the swing.
Shoulder Injuries Related to Golf • Subacromial tissue impingement can be worsened by rotator cuff imbalances, as well as tight posterior capsules and hypermobile glenohumeral joints. • During the take away phase the left shoulder forward flexes to at least 90 degrees, horizontally adducts to about 60 degrees, and slightly internally rotates. • Therefore left shoulder is placed at awkward position of flexion, internal rotation, and horizontal abduction. • This position can lead to impingement symptoms secondary to the greater tuberosity of the humerus riding up under the acromion.
Decreased Strength and Flexibility of the Shoulder • A decrease in shoulder joint range of motion produces excessive strain on the spine due to over rotation of the spine. • An increase in shoulder rotation will increase power and maintain proper club angles. • Tight levator scapulae affect neck rotation as well as optimal positioning of the shoulders during movement.
Decreased Strength and Flexibility of the Shoulder • Restriction in the right external rotators will produce a restriction in the follow through. • Restriction of the external rotators in the left shoulder will result in decreased ability to execute a full take away phase. • Tight pectorals will decrease shoulder turn and result in loss of external rotation in both shoulders.
Decreased Strength and Flexibility of the Shoulder • Other shoulder problems are weak rotator cuff muscles can cause poor swing mechanics and glenohumeral instability. • If scapulothoracic joint mobility is reduced, overcompensation will take place in the glenohumeral joint
References Maddalozzo, G.F. John (1987). An Anatomical and Biomechanical Analysis of the Full Golf Swing [Electronic Version]. NSCA Journal 9 (4), 6-8, 77-79. Hume, Patria A., Keogh, Justin, & Reid, Duncan (2005). The Role of Biomechanics in Maximising Distance and Accuracy of Golf Shots [Electronic Version]. SportsMed 35 (5), 429-449. Reed, Julian (2005). Strength and Conditioning Strategies to Reduce the Risk of Lower Back Injuries Associated with the Golf Swing [Electronic Version]. Strength and Conditioning Journal 27 (2), 10-13. Hetu, Frederick E. & Faigenbaum, Avery D. (1996). Conditioning for Golf: Guideline for Safe and Effective Training [Electronic Version]. Strength and Conditioning Journal, 22-28. Westcott, Wayne L., Doland, Fred & Cavicchi, Tom (1996). Golf and Strength Training are Compatible Activities [Electronic Version]. Strength and Conditioning Journal, 54-56. Draovitch, Peter & Westcott, Wayne Z. (1999). Complete Conditioning for Golf. Human Kinetics.
References cont… Gorman, J. (2001). In the swing: The shoulder’s role in this complex golf stroke. Sports Medicine Update, 15(3), 7-12. McHardy, A., & Pollard, H. (2005). Muscle activity during the golf swing. British Journal of Sports Medicine, 39(11), 799-804.
Questions 1.What is the main objective of the golf swing? A. Produce maximum distance B. Accuracy C. Control D. Consistency in each golf shot E. All of the above 2. What is not an active muscle used in the upper trunk during the back swing? A. Subscapularis B. Upper Serratus C. Upper & Middle Trapezius D. Semimembranosus
Questions 3. What phase of the golf swing is the action phase of Newton’s Third Law? A. Take Away B. Acceleration C. Forward Swing D. Early Follow Through 4. What phase of the golf swing is the reaction phase of Newton’s Third Law? A. Forward Swing B. Acceleration C. Forward Swing D. Early Follow Through
Questions 5. What is the most important role of the lever arm in the golf swing? A. Acceleration B. Maximum distance C. Control D. Consistency