Lenetsky, S, Brughelli, M, Nates, RJ, Cross, MR, and Lormier, AV. Variability and reliability of punching impact kinetics in untrained participants and experienced boxers. J Strength Cond Res 32(7): 1838-1842, 2017-Striking impact kinetics are central to performance in combat sports. Despite a multitude of assessment, few in the literature have explored the variability and reliability of punching force assessment. Consequently, this study assessed the variability and reliability of measured punching impact kinetics in untrained and experienced boxers using a recently developed and validated method of striking dynamometry. Intrasession (both cohorts) and intersession (untrained only) measures of impulse, peak, and mean force were determined across 4 punch types (jabs, crosses, lead, and rear hand hooks) using coefficient of variation (CV), intraclass correlation coefficients (ICCs), and typical error of measurement (TEM). Moderate (ICC <0.67 or CV >10%) to small (ICC >0.67 and CV <10%) variability was found for intrasession results of both groups, the majority having small variability. Intersession findings of the untrained cohort had a similar spread of variability, but with the majority exhibiting moderate variability. All variables except for mean force of the cross in the experienced boxer cohort were found to exhibit a "moderated" magnitude of reliability determined by standardized TEM scores (TEM = 0.60-1.19) during intrasession testing. All variables had moderate reliability during intersession. This method was found to have acceptable variability and reliability when monitoring punching impact kinetics.
BackgroundDespite the occurrence of the nasal cycle being well documented, the functional purpose of this phenomenon is not well understood. This investigation seeks to better understand the physiological objective of the nasal cycle in terms of airway health through the use of a computational nasal air-conditioning model.MethodA new state-variable heat and water mass transfer model is developed to predict airway surface liquid (ASL) hydration status within each nasal airway. Nasal geometry, based on in-vivo magnetic resonance imaging (MRI) data is used to apportion inter-nasal air flow.ResultsThe results demonstrate that the airway conducting the majority of the airflow also experiences a degree of ASL dehydration, as a consequence of undertaking the bulk of the heat and water mass transfer duties. In contrast, the reduced air conditioning demand within the other airway allows its ASL layer to remain sufficiently hydrated so as to support continuous mucociliary clearance.ConclusionsIt is quantitatively demonstrated in this work how the nasal cycle enables the upper airway to accommodate the contrasting roles of air conditioning and the removal of entrapped contaminants through fluctuation in airflow partitioning between each airway.
Lenetsky, S, Brughelli, M, Nates, RJ, Neville, JG, Cross, MR, and Lormier, AV. Defining the phases of boxing punches: A mixed-method approach. J Strength Cond Res 34(4): 1040–1051, 2020—Current research on punching in boxing has explored both kinematic and kinetic variables; however, there is no shared structure in the literature to describe these findings. A common method used to provide a shared structure in other sporting tasks is the definition of movement phases. To define the phases of 4 punches used in boxing (lead punches and rear straight and hook punches), 10 experienced and competitive boxers (age = 25.6 ± 5.97 years, height = 179.5 ± 7.72 cm, body mass = 95.66 ± 21.82 kg, and years training = 10.3 ± 5.97 years) were tested while performing maximal-effort punches. Ground reaction forces (GRFs), electromyographic, high-speed video (HSV), and striking dynamometry data were collected during all punches. A mixed-method approach was used to define the phases for each punch type based on the GRF measurements and impact timing from the striking dynamometer. Electromyographic and HSV data were then used to develop a more holistic understanding of punching actions by elaborating on the description of each phase. The final outcome of this approach has produced definitions for the phases of straight and hook punches, a greater qualitative understanding of said punches, and most importantly, a structure for current and future punching-related research, and a context to improve coach/sport scientist communication.
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