Boxing Biomechanical Analysis
Two of the basic starter punches used in boxing are the jab and the cross. This combination is known as the 1-2 and is one of the fundamental combinations.
Jab
Phase I- Jab Power Generation
The boxer starts with his feet shoulder width apart and your lead foot staggered in front about 12 inches and rear foot angled outwards slightly. You can see this in the picture below (Figure 1). The boxer takes a step forward with his lead foot, his left foot in this instance. This is in order for him to build some starting momentum to be transferred throughout the body and generate more force. The boxer rotates his torso bringing his lead shoulder forward and begins to extend his/her arm to full extension while rotating the fist 90 degrees clockwise. The boxer aims generally towards the central axis of the head. This phase is key in the power generation and getting the arm into position to move in for the punch. The both the acceleration and velocity should be near maximal by the end of this phase as we move into the power delivery phase.
Phase I- Jab Power Generation
The boxer starts with his feet shoulder width apart and your lead foot staggered in front about 12 inches and rear foot angled outwards slightly. You can see this in the picture below (Figure 1). The boxer takes a step forward with his lead foot, his left foot in this instance. This is in order for him to build some starting momentum to be transferred throughout the body and generate more force. The boxer rotates his torso bringing his lead shoulder forward and begins to extend his/her arm to full extension while rotating the fist 90 degrees clockwise. The boxer aims generally towards the central axis of the head. This phase is key in the power generation and getting the arm into position to move in for the punch. The both the acceleration and velocity should be near maximal by the end of this phase as we move into the power delivery phase.
Figure 1. The Starting Position
Phase II- Jab Power Delivery
After reaching peak velocity and peak acceleration during phase I, contact is made with the target. In this phase the hand is released in a controlled manner. Greater peak velocities establish greater contact forces, (Mack et al. 2010) The arm moves into full extension and the fist rotates, so that the boxer can strike with optimal mechanical positioning. Muscular force is required to stabilize the scapula and core throughout this phase. The picture below Illustrates what would be the moment of delivery, though in this case the boxer is not hitting an object (Figure 2).
After reaching peak velocity and peak acceleration during phase I, contact is made with the target. In this phase the hand is released in a controlled manner. Greater peak velocities establish greater contact forces, (Mack et al. 2010) The arm moves into full extension and the fist rotates, so that the boxer can strike with optimal mechanical positioning. Muscular force is required to stabilize the scapula and core throughout this phase. The picture below Illustrates what would be the moment of delivery, though in this case the boxer is not hitting an object (Figure 2).
Figure 2. The Jab
Phase III- Jab Power Transfer
Momentum is conserved throughout the jab, as generated momentum is transferred into the target. Equilibrium must be attained during impact, maintaining balance and integrity. This transfer of momentum represents phase III, and can be observed when an opponents head or a heavy bag moves in the opposite direction. If the boxers center of mass is not in equilibrium, balance will be lost during the transfer of momentum.
Momentum is conserved throughout the jab, as generated momentum is transferred into the target. Equilibrium must be attained during impact, maintaining balance and integrity. This transfer of momentum represents phase III, and can be observed when an opponents head or a heavy bag moves in the opposite direction. If the boxers center of mass is not in equilibrium, balance will be lost during the transfer of momentum.
Cross
Phase IV- Jab Return and Cross Power Generation
Following the transfer of jab momentum, the jab hand must quickly return to protect the face. This negative velocity serves as a counter movement, enabling power generation for the cross punch. The right hip rotates internally with the rear foot pivoting on the ball of the foot till toes are facing forward. The right shoulder rotates medially as well after the hip has initiated its rotation in order to produce additional momentum using the swing. The right elbow extends and the fist rotates counter clockwise aligning the proximal phalanges of the hand perpendicular to the floor. This phase produces greater peak velocities and accelerations, allowing the cross to serve as the more powerful punch in the combination.
Figure 3. The Cross
Phase V- Cross Power Delivery
The cross hand reaches peak velocity and peak acceleration just like the delivery phase for the jab and maintains this velocity until contact is made with the target. In the picture above it illustrates this delivery of the cross power (Figure 3). It is important to make sure that the you keep your chin tucked into your right shoulder and left hand up and guarding the left side of your face. The back foot should just finish its pivot when the delivery phase for the cross reaches its conclusion and we move into the cross power transfer phase, Phase V. Once again muscular force is required to stabilize the scapula and core throughout this phase.
The cross hand reaches peak velocity and peak acceleration just like the delivery phase for the jab and maintains this velocity until contact is made with the target. In the picture above it illustrates this delivery of the cross power (Figure 3). It is important to make sure that the you keep your chin tucked into your right shoulder and left hand up and guarding the left side of your face. The back foot should just finish its pivot when the delivery phase for the cross reaches its conclusion and we move into the cross power transfer phase, Phase V. Once again muscular force is required to stabilize the scapula and core throughout this phase.
Phase VI- Cross Power Transfer
Slightly more momentum is transferred through this punch since there's a greater peak velocity attained due to the counter movement. The energy is transferred from the boxers fist into his opponents head often causing the brain to move within the skull leading to many brain trauma injuries.
Slightly more momentum is transferred through this punch since there's a greater peak velocity attained due to the counter movement. The energy is transferred from the boxers fist into his opponents head often causing the brain to move within the skull leading to many brain trauma injuries.