Ballistic Bench Research Articles

Muscular Strength Is Associated with Higher Intraocular Pressure in Physically Active Males.

The positive association between intraocular pressure (IOP) and relative maximum force may have relevance for exercise recommendations when IOP is a concern. The relationship between exercise and IOP has been approached in several studies. However, the influence of muscle function on IOP remains underexplored. This study aimed to determine the relationship between the maximal mechanical capabilities of muscles to generate force, velocity, and power with IOP. Sixty-five physically active males participated in this cross-sectional study. Baseline IOP measures were obtained by rebound tonometry, and participants performed an incremental loading test in the ballistic bench press. Baseline IOP showed a strong positive correlation with relative maximum force (r65 = 0.85, P < .001) relative maximum power (r65 = 0.85, P < .001), and relative one-repetition maximum (r65 = 0.91, P < .001). Also, a moderate positive association was obtained between baseline IOP and maximum force (r65 = 0.74, P < .001), maximum power (r65 = 0.72, P < .001), and maximum dynamic strength (r65 = 0.80, P < .001). No significant correlations between IOP and maximal velocity were obtained (all P > .05). There is a positive association between greater upper-body power and strength with higher baseline IOP, which might have important implications in the management of ocular health and especially in individuals constantly involved in resistance training programs (e.g., military personnel, weightlifters). The possible protective effect of high fitness level on the acute IOP response to strength exercise needs to be addressed in future studies.

The Effects of Ballistic and Non-Ballistic Bench Press on Mechanical Work and Oxygen Uptake

The Effects of Ballistic and Non-Ballistic Bench Press on Mechanical Work and Oxygen Uptake

Experimental and numerical study of frictional heating during rapid interactions of a Ti6Al4V tribopair

Frictional work dissipated into a pair of bodies in contact can lead to the generation of high temperatures at the interface. For extreme conditions, knowledge of such temperatures is indispensable for predicting material damage. Friction experiments have been performed for a Ti6Al4V tribopair on a ballistic bench at elevated sliding velocities and at high normal pressure (V0=43–65m/s and p=110MPa). A specific foil-workpiece thermocouple was developed to measure interface temperature; it was determined that such a sensor is particularly well-adapted to severe interaction conditions (very short response times, adhesive wear and high plastic strain). The experimental study shows that under such extreme conditions, sliding velocity effects on maximum temperatures reached are quite negligible. Using experimentally measured friction coefficients, thermal finite element simulations were performed to examine thermal fields along a sliding path. The temperature and thickness of the heat-affected zone are in good agreement with our postmortem SEM observations, indicating that wear phenomena do not modify the temperature field. A complex partition of heat flux is observed due to differences in the temperatures of the bodies in contact, being accentuated by temperature dependent thermal diffusivity of the Ti6Al4V alloy. Based on these partition coefficients, gradients of dissipated energy along the sliding path are determined.