Master's thesis - - State University of New York College at Cortland, 2006 - - Department of Exercise Science and Sport Studies. / Includes bibliographical references (p.33-5).

Eccentric overload in training settings utilizes loads higher than concentric one repetition maximum (1RM). There is no clear definition of eccentric “failure” or 1RM using conventional weights, so eccentric 1RM is estimated to be between 145-190% concentric 1RM. Historically, the highest intensity used for eccentric overload is typically 120% of concentric 1RM despite little research using conventional weights with higher eccentric intensities. The purpose of this study was to conduct an exploratory neuro-mechanical analysis of different intensities of elbow flexors eccentric overload using free weights by examining angular kinematics during contraction. Twenty male participants with weight training experience had unilateral concentration curl isometric peak torque assessed on a Humac Norm Dynamometer and concentric 1RM assessed with dumbbells while biceps brachii electromyography (EMG) and elbow joint angle were recorded. Angles were recorded using a custom made electrogoniometer and elbow joint torque was estimated using inverse dynamics. Participants were randomly assigned in counter balanced order to perform eccentric actions at 120%, 140%, 150%, 160% and 170% concentric 1RM with 4 minutes rest between. Variables included peak torque, angular velocity at peak torque, impulse, power, mean EMG, and EMG normalized to peak. Data were analyzed using repeated measures ANOVA or a Friedman test. Angular velocity at peak torque was significantly lower for 120% (65.3 ± 40.8°/s) compared to all other conditions (range: 65.3 ± 40.8 to 162.1 ± 75.2°/s; p<0.01). Peak torque for all conditions (range: 98.2 ± 16.2 to 108.2 ± 21.6 Nm) was significantly higher than isometric peak torque (77.4 ± 16.8Nm; p<0.05). Peak torque at 160% (108.2 ± 21.6Nm) was significantly higher than at 120% (98.2 ± 16.2Nm; p<0.05). Power for 140-170% (range: 166.2 ± 85.7W to 265.8 ± 111.3W) was significantly higher than power at 120% (79.9 ± 66.8W; p<0.05). Impulse was highest at 120% (56.1 ± 54.6Nms) compared to all other conditions (range: 56.2 ± 54.6 to 9.6 ± 3.8Nms; p≤0.05). Impulse at 140% (20.6 ± 11.8Nms) was significantly higher than 170% (9.6 ± 3.8Nms; p<0.05). Isometric mean EMG (0.792 ± 0.285 mV) was significantly higher than all eccentric conditions (range: 0.654 ± 0.313 to 0.533 ± 0.259mV; p<0.05) with no difference between eccentric conditions for mean EMG or EMG normalized to peak. It was concluded that compared to 120%, eccentric overload with intensity ranging from 140-170% concentric 1RM involves minimal increases in peak torque and no change in EMG activation. Intensities above 120% enhance power and decrease impulse. This research has implications on future training prescription of eccentric exercise.

Preliminary normative standards are a tool clinical exercise specialists and health fitness instructors can use when interpreting muscular strength testing results. However, a challenge for professionals is evaluating an individual's one-repetition maximum (IRM) and relating that to others of the same age and gender, because there are no preliminary normative standards for 1RMs available when testing via free-weights and machines.This study conducted at Ball State University, Adult Physical Fitness Laboratory, examined results of muscular strength testing in order to obtain the normative muscular strength of adults. The purpose was to develop preliminary normative standards for strength of adults and to compare the 1RM weight an individual lifts between free-weights, Paramount, and Cybex machines. Seventy-nine healthy men and women between 18 and 79 years of age participated in the study. Subjects were tested on free weights, Paramount, and Cybex machines.Test results revealed preliminary normative standards for 1RM on free weights. Individuals were categorized in three age groups for the free-weight bench press and the Cybex (free-weight) Leg Press. The 18-23 year olds obtained a IRM mean (± Standard Deviation (SD)) of 200.6 + 32.8 lbs and 83.6 ± 18.5 lbs for men and women, respectively, for the free-weight bench press. The 43-59 year olds obtained a 1RM mean of 149.2 ± 41.8 lbs and 71.3 ± 8.6 lbs and the 60-79 year olds had a 1RM mean of 119.5 + 30.0 Ibs and 61.6 ± 15.6 lbs for men and women, respectively, for the free-weight bench press. The 18-23 year olds obtained a 1RM Cybex (free-weight) leg press mean of 484.9 + 58.0 lbs and 234.3 ± 67.5 lbs for men and women, respectively. The 43-59 year olds were able to obtain 1RM means of 444.4 + 84.9 lbs and 254.5 ± 51.7 lbs and the older subjects (60-79 years old) were able to obtain 1RM mean of 390.7 ± 98.6 lbs and 230.3 ± 76.6 lbs for men and women, respectively. Results were also documented in relative values by the amount of weight pushed divided by body weight for better comparison of individuals. Subjects generally lifted more weight on the Cybex (free-weight) leg press compared to the Cybex (machine) leg press. All subjects (N=79) had a mean and standard deviation of 294.9 + 87.7 lbs for the Cybex (machine) leg press (1RMs) and 343.4 ± 123.4 lbs on the Cybex (free-weight) leg press (1RMs). There was a significant difference between the Cybex (free-weight) leg press and the Cybex leg press (p<.001). The correlation for these two types of lifts was r=0.88. There was a significant difference between the free-weight bench press and the Paramount seated chest press (p<.001). The correlation for between the two types of lifts was r=0.93. / School of Physical Education, Sport, and Exercise Science