The manifestations of fatigue in amateur boxing performance

A subjective method of judgment, the “Ten Point Must-System” (TPMS), was introduced into amateur boxing in 2013. To be successful, boxers must deliver forceful punches and exert dominance over an opponent. There has been limited research examining the strategies used by boxers to win fights under the TPMS and whether these strategies induce fatigue that is sufficient to significantly affect punch force. The overall objective of the five studies contained in this thesis was to describe, in relation to fatigue, the performance characteristics of male amateur boxers under the TPMS, and improve our understanding of the physical characteristics associated with punch force production in highly-trained male amateur boxers. The first study describes technical and behavioural patterns as well as perceptions of effort and fatigue in winning and losing boxers during competition bouts. Winners were found to punch more accurately than losers (33% vs. 23% of punches were landed and 17% vs. 27% were air punches) but the total number of punches were similar. Clinch time, guard drops, and perceptions of effort and fatigue all increased, and bouncing decreased in all boxers over rounds. Regression analysis revealed that in combination, the percentage of punches landed and movement style correctly classified 85% of bout outcomes. Boxers appear to use tactical strategies throughout bouts to pace their effort and minimise fatigue, but these did not influence bout outcome. Thus, judges use several performance indicators, including punch accuracy (but not number) and movement style to (subjectively) assess dominance and determine a winner. To understand the interaction between punch force and fatigue-related behaviour, a boxingspecific, laboratory-based test (3-min punch test; 3MPT) was designed to measure punch force (N) and force-time variables (i.e. impulse and various rate of force development variables; RFD). The punch force measurement system had high mechanical reliability and accuracy (CV < 0.1%). Typical error and smallest worthwhile changes comparisons revealed that the 3MPT could detect moderate and large changes in performance, however within-day reliability improved from day 1 - 2 (CVs of 3.1 - 13.8% vs. 2.3 - 5.1%), indicating a possible learning effect. Thus, repeat-trial familiarisation is suggested to reduce between-test variability. Studies 3 - 5 then utilised this system to examine factors that may influence punch force delivery. In Study 3, correlation and regression analyses revealed significant (p < 0.05) relationships between peak punch force and forces measured in countermovement jump and isometric mid thigh pull tests (i.e. lower-body strength) as well as body mass, but not RFD, in the lower body. No meaningful relationships between punch performance characteristics and any upper-body strength or power parameters were identified. The results of Study 3 show lower-body strength, but not RFD was significantly and positively related to peak punch force, however upper-body strength and power did not discriminate between boxers who punched with higher or lower peak force. In Study 4, punch force characteristics, were measured in the 3MPT of highlytrained male amateur boxers before (ROWpre) and after (ROWpost) 9 × 1-min bouts of rowing. This was designed to induce fatigue in lower limb, trunk, and arm flexion muscles whilst leaving arm extensor muscles (primary punch muscles) non-fatigued. Significant reductions in punch force were found ROWpost compared to ROWpre for all punch types, and significant delays in the time to reach specific force levels and relative percentages of peak force (i.e. RFD) occurred in all punches except the jab. Thus, punches that particularly rely on lower-limb force production and trunk rotation (crosses and hooks) were most affected. Speculatively, ground reaction force generation was affected by fatigue, however since the jab relies predominantly on arm extension, punch force was less affected by lower-limb fatigue. In Study 5, the effect of non-specific muscle fatigue (rowing; ROW; as described in Study 4) on punch force production was also examined using the 3MPT, with additional comparisons between control (CON; 75 min rest) and boxing (BOX; competitive boxing bout [3 × 3 min]) conditions in a population of highly-trained male amateur boxers. Significant punch force reductions from ROWpre to ROWpost in lead-hand hooks and jabs were observed, however no significant differences were present in CON or BOX, and RFD variables remained unchanged in all conditions. These results suggest that reductions in punch performance after rowing arise from fatigue in the lower body and trunk muscles, whilst boxing is likely to cause fatigue in other body segments that have less influence on punch force production; it is also speculated that boxers use pacing strategies to maintain punch force during fatiguing boxing bouts. The general findings of this thesis were: technical and behavioural (possibly altered by fatigue) actions influence judge perception under the TPMS, and success requires high levels of punch accuracy; lower-body (but not upper-body) strength rather than RFD was associated with punch force production; lower-body and trunk fatigue significantly reduced punch force, supporting the theory lower-body strength is important to produce punch force; and, boxers maintained the ability to produce punch force throughout a boxing bout, possibly because fatigue was not accumulated in the lower limb and trunk muscles (partly due to boxers using pacing strategies).