Close this panel
Browse By Date
Browse By Track
Browse By Poster Author
Browse By Title
Browse By Poster Number
Close this panel



Seth M. Lenetsky, PhD – Research Associate, Auckland University of Technology

Matt Brughelli – Senior Lecturer, Auckland University of Technology

Roy J. Nates – Associate Professor, Auckland University of Technology

Jonathan G. Neville – Research Fellow, Auckland University of Technology

Matt R. Cross – PhD Student, Univ Savoie Mont Blanc

Anna V. Lorimer – Assistant Professor, Bond University

Kristin J. Heumann, PhD, CSCS, c-EP – Associate Professor , Colorado Mesa University


INTRODUCTION: Effective mass (EM), an athlete’s inertial contribution to a strike, has been identified as a key impact kinetic in punching. While double peak muscle activation (DPMA) has been theorised as vital to the development of EM, no studies have empirically identified its determinants. PURPOSE: To investigate the relationship between ground reaction forces (GRF) and electromyographic (EMG) to EM in the jab of a cohort of experienced boxers. METHODS: 10 experienced and competitive male boxers (age = 25.6 years ± 5.97, height = 179.5 cm ± 7.72, mass = 95.66 kg ± 21.82, and years training = 10.3 years ± 5.97) participated in this study. The following muscles were prepared for EMG data collection: triceps brachii (LTB and RTB), latissimus dorsi (LLD and RLD), rectus abdominis (LRA and RRA), and rectus femoris (LRF and RRF) of the lead and rear sides. After preparation, participants performed a standardised warm-up, maximal voluntary isometric contractions for EMG normalization, and familiarisation. Five maximal punches against an instrumented bag were used for analysis. Trials were recorded with an EMG system, 2 force plates (1 plate under each leg), 2D high speed video (HSV), and an instrumented bag to measure impact kinetics; all devices sampled at 1000 Hz, were time synchronised to impact. 2D HSV was used to determine pre-impact punch velocity of the jabs which was used to calculate EM with impulse measured through the instrumented bag. A hierarchical regression using magnitude-based inference was employed to identify the determinants of EM. Pearson correlation coefficient (r) and co-efficient of determination () were calculated for each model. Inferences based on the square-root of the  were used to describe the magnitude of the observed relationship. A 5:1 ratio of boxers to independent variables (10 boxers = maximum of 2 independent variables) was used to account for shrinkage and inflated error rates due to the study’s relatively small sample size. RESULTS: EM was determined by the GRF variables of minimal lead leg X axis value during the impact phase (force applied towards the boxer’s mid-line) and max GRF development in the lead leg (Y axis) during the execution phase. Both variables had negative relationships with EM. RTB results were the final EMG determinants of EM in the jab. RTB duration of activation had a negative relationship (r = -0.51) and the phase of activation start had a positive relationship (r = 0.41) with EM. The key determinants of EM in the jab were minimal lead leg GRF (X axis) and the duration of activation of the RTB. CONCLUSION: These findings contrast with the theory of optimizing EM. Instead of DPMA being a primary determinant of EM, two variables which optimize the rotation of the torso were key to the development of EM in the jab. PRACTICAL APPLICATION: These results indicate that to improve EM in the jab of boxers, practitioners should focus on improving rotational performance over methods thought to improve DPMA.


Rate This Poster

Stuff for notes
Stuff for Message board

Share Poster


Technical Support

(877) 426-6323


SUBMIT FEEDBACKfeedback icon

We really appreciate your feedback on the eventScribe website. We use the data to improve the experience and simplify the process for users like you.


Log In / Sign Up

Already have an Event Scheduler or mobile app login? Login with those details. If not, create a login.

Log In   Sign Up
Access your bookmarked poster and notes by logging in ...   Sign up to take notes on poster, bookmark poster, and submit feedback.
  Lost your access key?      
You need to be logged in to bookmark posters, save notes, or rate posters.