Part 2 - Punching Back: Summation of Forces

When it comes to increasing punching force for a combat athlete, understanding that force is generated from the lower body is only part of the equation.  Studies on boxers as well as other sport athletes (baseball, tennis) that follow similar lower body – trunk mechanics have shown for years how important the lower body is for force generation.  It is the understanding of how the force is transferred into the punch that will make a huge difference towards the practical application for strength and conditioning coaches.  In the study that was sited in the article[1], it was found that the rear leg push-off contributed close to 39% of the force, trunk rotation was responsible for 37% of the force, and arm extension making up the rest at 24%[2].  
In order to get force from the legs into the punch, you must start with a weight shift onto the front leg.   As noted in the studies by Filmonov[3] [4], the weight shift  (“push-off leg extension”) is the main source of force production.  It is important to get the hips in motion in order to overcome inertial and get the body in motion and to direct the forces towards your target.  The joint actions are right hip  abduction with hip internal rotation. Once the weight has been shifted onto the front leg, it is now the base of support and the left hip becomes the axis of rotation for the pelvis and the shoulder girdle.  It is important that the front leg be held stiff (isometric contraction), so that the weight shift can be transferred to the hip and trunk rotation.  The greater that the front leg sinks, the more of the forces from the weight shift will be lost.   As the hips rotate forward around the left hip, the shoulders must still be side facing which creates a separation between the hips and the shoulders.  This separation causes an eccentric stretching of the right external and the left internal oblique muscles while the shoulders are still facing the side position.  The forward hip rotation prepares for a forceful rotation of the shoulders.  Once the hips decelerate into the front facing position, they contract isometrically creating a firm base for the oblique’s to contract and rotate the shoulders.  This action produces mechanically a long force arm.  As the hips decelerate, the shoulders begin to rotate due to a concentric contraction of the right and left obliques.[5]  “The lag between pelvis rotation and upper trunk rotation is critical for generating energy from the trunk that is passed along to the throwing arm. Without proper timing of pelvis and upper trunk rotation, the athlete may have low-ball speed and/or excessive loads in the shoulder and elbow.”[6]  The greater the force of the shoulder rotation contributes to creating greater arm speed.
It is the summation of forces from the joint actions that follow a specific progression that culminates in maximum force.  Understanding these actions and how they produce force then allows for the physical preparation coach to select exercises to improve punching force.  “Each joint action must occur in sequence so that the force generated by one action can then be transferred to the next action. When the force generated from one joint action is transferred to the next joint, such as the legs to the hips to the shoulders to the arm to the wrist… it allows for the culmination of maximum force (and speed).”[7] Therefore the most efficient and powerful actions occur when the force from the preceding joint is added on to the next joint action.  For this to occur, all of the joint actions cannot occur simultaneously, they must occur in a sequence with some overlapping between them if you are to generate maximum force. 

            Part 3 will give some practical examples of general and specialized exercises that a physical preparation coach use in order to increase punching force. 

[1] Lenetsky.  Harris.  Brughelli. “Assessment and Contributors of Punching Forces in Combat Sports Athletes: Implications for Strength and Conditioning.  NSCA- Strength and Conditioning Journal.  Vol. 35 #2
[2] Filimonov. Means of Increasing Strength of the Punch.  NSCA Journal. Vol 7, #6
[3] Filimonov. Means of Increasing Strength of the Punch.  NSCA Journal. Vol 7, #6
[4] Verkhoshansky. Filimonov. The Dynamics of Punching Technique and Speed-Strength in Young Boxers.  Soviet Sports Review. Vol. 26, #4
[5] Yessis. Sports Performance Series: Throwing a Football. NSCA Journal. Feb-Mar 1984
[6] Fleisig. Biomechanics of Baseball Pitching: Implications for Injury and Performance.
American Sports Medicine Institute, Birmingham, AL, USA.  XXVIII International Symposium of Biomechanics in Sports
[7] Yessis.  Explosive Tennis.