# Biomechanics of Punching--The Impact of Effective Mass and Force Transfer on Strike Performance
## 2 Materials and Methods
### Protocol  
The methodological framework was based in part on our previous study [5], which investigated effective mass in straight punches performed without gloves. However, the present study extends this protocol by including hook techniques and applying a more ecologically valid condition using standard 16-oz boxing gloves. These modifications aimed to replicate real training and competitive scenarios more accurately. The experiment took place at the University's Center for Human Movement Analysis. Participants underwent preliminary health checks to confirm their eligibility--they submitted a written declaration stating they were free from injuries or conditions that could affect the outcome of the study After providing informed consent, they engaged in a 10-min warm-up routine consisting of various dynamic exercises, such as jumps, rotations, and simulated punches. Following this, they practiced striking a target equipped with the force plate to ensure proper alignment and familiarity with the apparatus. Each participant performed 10 strikes with each of the four techniques to familiarize themselves with the device's specifications and its shock-absorbing properties. The decision was made to perform strikes with gloves rather than bare fits. This approach preserved the natural working environment for boxers, who typically do not execute strikes without gloves in their daily practice. This also ensures that the athletes strike with maximum force, without subconsciously holding back to protect their hands. Sixteen-ounce gloves were used, which is a standard training size for boxing athletes. The gloves, manufactured by Orthodox Wear, feature a typical boxing-style profile. For the main experiment, the sensor was first attached to the non-dominant arm, and participants performed ten high-force strikes--five jabs and five lead hooks with rest time corresponding to the requirement of rerunning the record and changing position (2-5 s). Then, there was a rest period for the time to transfer the sensor to the dominant arm (around 1 min), allowing participants to execute another ten strikes with their rear hand--five crosses and five rear hooks. Sensor repositioning provided natural rest intervals between trials. We exclude the possibility of fatigue effect for athletes at that level. During normal training sessions, boxers hit a punching bag dozens of times, therefore 20 hits within a short period of time and short rest could not affect their performance. To investigate potential  
Figure 1: Research equipment: (**A**) force plate AMTI MC12-2K with a strike pad; (**B**) EMU sensor on upper limb. fatigue effects, the reliability of pressure force measurements across repeated punch trials was assessed using the Intraclass Correlation Coefficient (ICC). ICC was calculated using a two-way mixed-effects model, considering each participant as a random effect and trials as repeated measures within each punch type. Specifically, this approach partitions variance into between-subject and within-subject components, quantifying how consistently each participant performed across their trials. The resulting ICC values indicated good-to-excellent reliability for all punch types: jab (ICC = 0.85), cross (ICC = 0.89), lead hook (ICC = 0.93), and rear hook (ICC = 0.82). High internal consistency of the results appears to confirm the minimal impact of fatigue on the athletes' performance during testing. Jabs are quick, straight punches performed with the lead hand, requiring minimal torso rotation. This punch primarily targets the opponent's upper body or head and serves as a fundamental tool for controlling distance and setting up combinations. The jab begins with a slight push from the lead foot, transferring energy through the leg and core. The lead shoulder flexion goes vertically as the arm fully extends vertically in the elbow joint in a straight line, with the forearm rotating slightly inward upon impact.