J. Lon Kilgore

Force-time curve characteristics and hormonal alterations during an eleven-week training period in elite women weightlifters.

The purpose of this investigation was to study the effects of an 11-week training period performed by female weightlifters. Two weeks before this investigation, baseline measures for total testosterone, cortisol, and testosterone:cortisol ratio were collected. The 11-week training program consisted of the core exercises (i.e., clean, clean and jerk, and snatch) and other supplemental exercises (i.e., clean pull, snatch pull, squat, and front squat). Hormonal, isometric, and dynamic middle thigh pull force-time curve characteristics were assessed biweekly throughout the duration of the investigation, whereas volume load and training intensity were assessed weekly throughout the investigation. The testosterone:cortisol ratio of the baseline (1.19 ± 0.64) was significantly different from the ratio of weeks 1 (0.67 ± 0.36) and 9 (0.94 ± 0.66). When the week-to-week values were compared, week 1 (0.67 ± 0.36) was significantly different (P < 0.05; &eegr;2 = 0.84) from week 3 (1.06 ± 0.54). A very strong correlation (r = −0.83; r2 = 0.69) was found between the percentage change of the testosterone:cortisol ratio and volume load from weeks 1 to 11. Moderate to very strong correlations were noted between the percentage change in volume load and isometric peak force, peak force during the 30% isometric peak force trial, and peak force during the 100-kg trial during the 11 weeks of training. The primary finding of this study was that alterations in training volume load can result in concomitant changes in the anabolic-to-catabolic balance, as indicated by the testosterone:cortisol ratio, and the ability to generate maximal forces.

Snatch Technique of United States National Level Weightlifters

Abstract Whitehead, PN, Schilling, BK, Stone, MH, Kilgore, JL, and Chiu, LZF. Snatch technique of United States national level weightlifters. J Strength Cond Res 28(3): 587–591, 2014—This study analyzed the top 3 successful snatch attempts by individual lifters in each weight class at a U.S. National Championship weightlifting meet. Two-dimensional (2-D) body position and characteristics of the lifts were compared via 2D video analysis in groups of lifters who displaced forward, showed no displacement, or displaced backward to receive the bar. No significant group differences (p > 0.05) were noted for body mass, bar mass, or hip angle. The rearward displacement group had a significantly greater horizontal distance between the shoulder and heel at the end of the pull (determined as the point where the bar ceases to accelerate vertically). Hip angles for the no displacement group had a small-to-moderate effect size (0.50) in comparison to the forward displacement group, but they only showed a small effect size (0.17) when compared with the rearward displacement group. The forward displacement group showed a small-to-moderate effect size compared with both the no displacement group (0.51) and the rearward displacement group (0.55) concerning the horizontal distance from the shoulder to the heel. These data seem to suggest that rearward displacement in the drop-under phase in the snatch is not detrimental to performance and actually seems to be a preferred technique in U.S. national level lifters. In addition to evidence that rearward displacement is exhibited in elite lifters and is coached globally, it seems this is the preferred technique in international competitions. This technique may be considered a viable variation of the snatch by coaches and athletes of all levels.

Determination of Ventilatory Threshold Through Quadratic Regression Analysis

Gregg, JS, Wyatt, FB, and Kilgore, JL. Determination of ventilatory threshold through quadratic regression analysis. J Strength Cond Res 24(9): 2512-2515, 2010-Ventilatory threshold (VT) has been used to measure physiological occurrences in athletes through models via gas analysis with limited accuracy. The purpose of this study is to establish a mathematical model to more accurately detect the ventilatory threshold using the ventilatory equivalent of carbon dioxide (VE/&OV0312;CO2) and the ventilatory equivalent of oxygen (VE/&OV0312;o2). The methodology is primarily a mathematical analysis of data. The raw data used were archived from the cardiorespiratory laboratory in the Department of Kinesiology at Midwestern State University. Procedures for archived data collection included breath-by-breath gas analysis averaged every 20 seconds (ParVoMedics™, TrueMax 2400). A ramp protocol on a Velotron™ bicycle ergometer was used with increased work at 25 W·min−1 beginning with 150 W, until volitional fatigue. The subjects consisted of 27 healthy, trained cyclists with age ranging from 18 to 50 years. All subjects signed a university approved informed consent before testing. Graphic scatterplots and statistical regression analyses were performed to establish the crossover and subsequent dissociation of &OV0312;E/&OV0312;o2 to &OV0312;E/&OV0312;CO2. A polynomial trend line along the scatterplots for &OV0312;E/&OV0312;O2 and &OV0312;E/&OV0312;CO2 was used because of the high correlation coefficient, the coefficient of determination, and trend line. The equations derived from the scatterplots and trend lines were quadratic in nature because they have a polynomial degree of 2. A graphing calculator in conjunction with a spreadsheet was used to find the exact point of intersection of the 2 trend lines. After the quadratic regression analysis, the exact point of &OV0312;E/&OV0312;o2 and &OV0312;E/&OV0312;CO2 crossover was established as the VT. This application will allow investigators to more accurately determine the VT in subsequent research.