Browsing by Subject "Muscle strength"
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Item A comparison between the leg power test and the vertical jump test as predictors of motor performance(Texas Tech University, 1968-08) Huffman, Walter BurlNot availableItem A comparison of four strength maintenance programs for football players(Texas Tech University, 1969-08) Gay, Robert AllenNot availableItem A Comparison of Four Strength Maintenance Programs for the In-Season Football Program(Texas Tech University, 1971-08) Bundy, William BlairNot Available.Item Alternative strength testing methods for employee screening(Texas Tech University, 1983-12) Plott, Christopher CNot availableItem Comparison between speed of movement and load under two muscular conditions(Texas Tech University, 1968-05) Mathus, Don LarryNot availableItem Comparison between the strength index test and predicted dynamic strength test as predictors of motor ability(Texas Tech University, 1968-06) Bowe, Gary DonNot availableItem Comparison of the relationships between physical fitness and dynamic and static strength(Texas Tech University, 1965-08) Blaschke, Leon AudreyNot availableItem Grip strength of telecommunication workers thirty to forty years of age(Texas Tech University, 1986-12) McKenzie, Freddy NedThe hand is used in nearly all physical work activities and is the recipient of more work injuries than any other part of the body except the trunk. In 1983 there were 360,000 disabling injuries to the hand and fingers (Accident Facts, 1984) . Accident statistics in some industries suggest that cumulative hand trauma disorders (CHTD) result in up to 50 percent of the total hand injuries as listed in Table 1.1.Item Hip Extension Strength and Knee Extension Strength at Various Knee Angles(Texas Tech University, 1967-08) Herod, Emitt LNot Available.Item Human motor unit synchrony and its relation to force steadiness(2007) Terry, Charles Kevin, 1961-; Griffin, Lisa; Rylander, H. Grady (Henry Grady), 1948-Motor unit synchronization is phenomenon driven by a common input that results in the near-simultaneous firing of two or more motor units, which is referred to as short-term synchronization. The relationship between motor unit synchronization and force steadiness is still unclear, even after numerous experiments and simulations. Our main hypothesis was that the decreased force tetanus brought on by motor unit synchronization would be correlated to reduced steadiness at very low hand muscle forces. To determine if this correlation existed, young, healthy adults performed a submaximal, isometric pinch at four forces to determine if motor unit synchronization increased with a progressive decrease in force steadiness driven by reduced force levels. However, before performing synchronization analyses, we had to establish the best technique for measuring motor unit coherence, which quantifies the strength and frequency of a periodic common input. We used a pool of simulated spike trains with various firing rates, coefficients of variation (CV), common input frequencies and trial durations to explore the effects of data segmentation and spike train properties on coherence. We found that tapered segments overlapped by at least 50% maximized coherence measurements, regardless of taper type and that increasing common input frequency CV from 0.15-0.50 made coherence measurements unusable, even at high synchronization levels. During an isometric pinch at 2, 4, 8, and 12% of maximum digit force, we recorded thumb and index finger forces and EMG from the first dorsal interosseous (FDI) and adductor pollicis (AdP) muscles. As expected, the force CV dropped as each digit force increased. Pooled coherence revealed a dominant peak for the 2-10 Hz, but power for both digits' forces was limited to the 0-2 Hz bandwidth. There was a weak correlation for thumb force CV and coherence for within-AdP pairs, but no significant correlations were found for within-FDI pair coherence and finger force CV. Therefore, motor unit synchronization was not a strong driver of force steadiness for this protocol. To ensure that inherent firing rate nonstationarity of spike train data did not affect coherence measurements, we produced a new set of spike train pairs with firing rates and variances that approximated those for physiological motor units, which varied from 0-25%. Stationarity level was not significantly correlated to peak coherence (max R² = 0.082). Therefore, coherence measurements of spike train data with characteristics similar to those of the simulated trains were not significantly affected by nonstationarity. The establishment of the best method for computing coherence, the lack of a strong correlation between force steadiness and motor unit synchronization for submaximal isometric forces, and the knowledge that spike train nonstationarity has no significant effect on coherence measurements are all important discoveries needed for progress in the areas of basic neuromuscular function, motor unit synchronization, and pathological force unsteadiness.Item Isokinetic Cybex 11 protocol comparisons(Texas Tech University, 1981-12) O'Keefe, MeganNot availableItem Isokinetic strength testing of the elbow joint using the Cybex II dynamometer(Texas Tech University, 1988-12) Rowell, Marilyn AnnNot availableItem Muscular force of elbow extension in the standing press(Texas Tech University, 1968-08) King, Ronal DeanNot availableItem Power as a predictor of lifting capacity(Texas Tech University, 1996-05) Dempsey, Patrick G.An experiment was conducted to examine the role that maximal lifting power has in predicting the maximum acceptable weight of lift (MAWL) for a frequency of one lift per 8 hours. The secondary aim of the study was to compare the ability of power to predict MAWL to previously used measures of capacity, including two measures of isometric strength, five measures of isokinetic strength, and isoinertial capacity on an isoinertial incremental lifting test. Twenty-five male subjects volunteered to participate in the experiment, and were examined by a physician prior to participation to ensure fimess for the experimental tasks. The experimental tasks were comprised of isometric, isokinetic, and isoinertial tests. The isometric tests involved maximum voluntary contractions for composite lifting tests at vertical heights of 15 and 75 cm. Peak isokinetic strength was measured at velocities of 0.1 m. • sec.'l, 0.2 m. • see."^ 0.4 m. • sec^, 0.6 m. • see."^ and 0.8 m. • sec."^ using a modified CYBEX II isokinetic dynamometer. Isoinertial lifting capacity was measured on the incremental lifting machine and peak power was measured on the incremental lifting machine by having subjects lift a 25 kg. load as quickly as possible. The results indicate that peak isoinertial power is significandy correlated with MAWL, and this correlation was higher than any of the correlations between the other predictor variables and MAWL. The relationships between the isokinetic strength measures and MAWL were stronger than the relationships between the isometric measures and MAWL. The magnitudes of the strength measures compared favorably with the values from previous studies. The mean MAWL value was shghtly lower than comparable values from databases in the hterature that are based on indusuial subject pools. The results provide indirect support for the hypothesis that lifting capacity and dynamic strength tests may be affected by the distribution of slow- and fast-twitch muscle fibers. Overall, the results suggest that tests used to predict MAWL should be dynamic rather than static. Suggestions for future research are presented which include repHcating the study with female subjects and an industrial subject pool.Item Reaction time and strength in pregnant and nonpregnant employed women(Texas Tech University, 1985-08) Masten, W. Yondell BinghamNot availableItem Relationship between static and dynamic strength at selected angles of the knee(Texas Tech University, 1967-08) Higginbotham, Robert BNot availableItem Simulated dynamic lifting strength models for manual lifting(Texas Tech University, 1983-05) Aghazadeh, FereydounAn experiment was designed and conducted for the development of the mathematical models for prediction of the weight lifting capacity of individuals for lifting a box and a bag from floor to shoulder height and knuckle to shoulder height at frequencies of 2 and 6 lifts per minute. The dependent variable was the maximum acceptable amount of lift and the independent variables were task- and operator-related. The operator variables included the dynamic strength of the subjects in a simulated lifting position, static strengths, height, weight, endurance, and the physical work capacity. The task variables were container type, lift type, and frequency of the lift. A total of nine males participated in this experiment as the subjects. During a period of one month (June, 1982) the required anthropometric', strengths', and lifting data were collected. The SAS procedures were used to develop and test the models. The data from six subjects were used to develop a total of 18 models (nine dynamic and nine static). The data from the three remaining subjects along with the data from the previous studies (available in the literature) were used to test and validate the models. I t was concluded that both the dynamic models and the static models developed in this study can predict the maximum acceptable amount of lift with a reasonable degree of accuracy. However, a comparison of the static and dynamic models revealed that the use of the dynamic models reduced the average absolute error between the actual and predicted load up to 44 percent. A simple dynamic model involving only one operator strength measure was thus found to be a good predictor of lifting capacity and was superior to the static models.Item Strength and its relationship to throwing a baseball for distance and accuracy(Texas Tech University, 1969-08) Saunders, MarkThe purpose of this study was to determine if actual strength in the hand, the arm, and the shoulder when compared with strength in the lower portion of the body contributed significantly to the performance of throwing maximum distances and to throwing accuracy from various distances. Thirty varsity baseball players, participating in organized high school baseball at Coronado High School, Lubbock, Texas, v/ere divided into three groups of ten. Each group consisted of varsity players who ranged in ages from 15 to 18 years. The groups were formed as follows: The participants were placed into groups by conducting a throwing test for distance. The players were ranked from one through thirty and were arbitrarily chosen 1, 2, 3, and 1, 2, 3 until the thirty subjects were placed in their respective groups. Group I (N=10) participated in all baseball fundamental drills such as hitting, fielding, throwing, and running. This practice session covered a duration of approximately one and one-half hours. Thirty minutes running and lower body weight training followed. Each individual was required to run five 50-yard sprints. This group also did ten repetitions of knee bends with gradual addition of weights, leg lifts with gradual addition of weights, and Jump rope (20 second intervals). Group II, however, dedicated thirty minutes to throwing weighted baseballs (10 ounces) and to conducting wristrolls, forearm curls, bench presses, and push-ups with progressive weight addition. Ten repetitions of each were performed each day of the training program. Subjects followed their respective programs for two months, three times weekly. Group III participated only in the daily baseball workout with no special training afterwards. All subjects were given a throwing test at the beginning and at the end of the two months period. Ten throws were made at each of the three distances to a target three feet in diameter placed four feet above the ground. The three distances were 75j 90, and 105 feet, and the target was of a circular shape. A total of thirty throws was made by each participant. The three-foot target size was decided upon because an average player can cover this area to fulfill a catch. Each of the members of the three groups also threw three times for distance, and the longest of the three throws was used in cybernation. There were no restrictions on how the ball was to be thrown in relation to form. Each of the balls thrown in accuracy testing and distance testing was retrieved from the ground in order to fulfill the act of throwing after fielding a batted baseball. The findings were as follows: 1. The effects of lower body weight training for eight weeks did not yield statistically significant differences in increase of throwing distance and accuracy within the group. 2. The effects of the upper body weight training for eight weeks did not yield statistically significant differences in increase of throwing for distance and accuracy within the group. 3. The effects of the control group with no training for eight weeks did not yield significant differences in increase of throwing for distance and accuracy within the group. 4. There was no statistically significant difference between the groups in the improvement of throwing distances. 5. There was no statistically significant difference between the groups in the improvement of accuracy from 75^ 90, and 105 feet. The following conclusions were reached from the findings of this study: 1. There was no statistically significant difference between any of the three groups tested in this study (lower body weight training, upper body weight training, and control group). 2. There would seem to be no Justification for conducting weight training programs to improve throwing accuracy and distance during the course of a season in basesball.Item Strength and motor ability as factors in attitude toward physical education(Texas Tech University, 1967-08) Layne, Robert A.Not availableItem The effect of isometric exercise on specificity and cross-transfer of muscular strength in the elbow flexor muscles(Texas Tech University, 1970-08) Edwards, John LynnNot available