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1.
Abstract

The theory proposes a nonconscious mechanism that uses stored information (motor memory) to channel existing nervous impulses from brain waves and general afferent stimuli into the appropriate neuromotor coordination centers, subcenters, and efferent nerves, thus causing the desired movement. A consequent hypothesis requires that the simple reaction time will become longer when the response movement is required to be of greater complexity. Data obtained on college men and women, and 12- and 8-year-old boys, are in agreement with the hypothesis. Replacing a very simple finger movement with an arm movement of moderate complexity slows the reaction by about 20 percent; additional complexity produces a further slowing of 7 percent. The speed of the arm movement is considerably faster in college men than in younger boys or in college women. The correlation between reaction time and speed of movement averages approximately zero. Individual differences in ability to make a fast arm movement are about 70 percent specific to the particular movement being made; “general ability for arm speed” occurs only to the extent of 30 percent.  相似文献   

2.
Abstract

College men and women were tested as to reaction time and speed of an arm movement using both motor-oriented and stimulus-oriented set. The results confirmed a hypothesis based on neuromotor coordination theory that predicted slower movement and greater reaction latency when the motor set was used. However, the 20 percent of subjects who had a natural motor set tendency moved faster with an enforced motor set than with an enforced sensory set. The conditions of enforced set caused a moderate positive correlation between reaction and movement times. Women subjects reacted and moved slower than men, but were similarly influenced by the two enforced set conditions. Their natural set tendency was definitely stimulus-oriented, while men tended to have a neutral orientation.  相似文献   

3.
Abstract

A horizontal adductive arm swing executed at maximal speed, and timed at intervals of 15°, 53°, 90°, and 105°, was studied under two experimental conditions. Although the movement completed was the same in both conditions, the fundamental difference between the “normal” and “pre-tensed” arm movements was that in the latter condition the subject built up his arm strength maximally just prior to initiating the movement. Twenty trials under each condition was performed by 60 college men. All reliability coefficients were found to be high, i.e., over .89. In contradiction to expectations, the relationship between premovement strength and speed of movement at the first station (r = -.208) was lower than anticipated. However, the low correlations found between strength and speed of movement are in general agreement with the results of earlier investigators which have substantiated the predominance of neuromotor specificity.  相似文献   

4.
Abstract

The experiment was designed to compare the effects of isometric-isotonic (A), dynamic-overload (B), and free swing (C) exercise programs on the speed and strength of a lateral arm movement The 26 college men in each group—three experimental and one control—were given pre- and post-training speed and strength trials. Each experimental group performed its assigned exercise twice a week during the 10-week training period. Reliability coefficients for both strength and speed of movement measurements were found to be high. Following training there were significant speed increases in both the isometric-isotonic and dynamic-overload groups (t=10.06 and 8.10; however, the difference in speed gain between conditions was nonsignificant (F=.10). Also, strength increases in both of these groups were significant (t=8.81 and 3.08), with that of the isometric-isotonic group significantly greater than the dynamic-overload group (F=5.11). No significant speed or strength gains were registered by either the free swing or control group.  相似文献   

5.
Abstract

The purpose of this study was twofold: to determine which exercise program was most effective in producing a static strength gain and to determine the relationship between static strength and speed of movement. Seventy-two eighth grade girls were divided into two experimental groups one using an isometric exercise program, the other using an isotonic program. A control group played lead-up games during the experimental period. Strength and speed of the arm and shoulder girdle were both measured by three tests. Prior to training, correlations indicated a rather high relationship between static strength, and speed of a dominant arm movement. Following training there was little relationship between static strength, and speed of a specific arm movement. The results of the training program indicated an increase in mean performance in all three groups with the isotonic group being superior.  相似文献   

6.
Abstract

This study investigated the relationship between strength and speed of forearm flexion and compared the effect of three methods of training on speed of forearm flexion movement. Ninety-one university freshmen were tested for maximum static strength, forearm mass, and speed of forearm flexion. They were assigned to four groups: control, speed of movement, isometric, and isotonic. After an 8-week experimental program, subjects were tested again for strength, mass, and speed of forearm flexion movement. Low positive relationships, significant at the .05 level, between static strength and speed of forearm flexion were found in this study. When static strength was related to the mass which was moved during movement, correlations between strength/mass and speed were not significant. The results of both correlational computations and covariance analysis indicated that increasing the strength of the muscles which move a limb does not result in a corresponding increase in the speed with which the limb can be moved.  相似文献   

7.
Abstract

Tests were made with the hand carrying weights of 0.2, 3.1, and 16.6 kg. during a 72° horizontal adductive arm swing of maximal speed timed at 12° intervals. Five practice swings and 20 trials, under each condition, were performed by 60 male subjects. Reliability coefficients were high. The first 24° of movement exhibited declining acceleration, followed by linearly increasing acceleration for the 24°—60° interval and deceleration for the next 12°. Compared with static strength in the movement position, action strength computed from acceleration was much greater with the heaviest weight and considerably less with the light weights. The correlation between static strength and speed was quite low for the normal arm swing but increased with added weight, becoming r = .76 for the heaviest. There was little correlation of individual differences in speed between different phases of movement or between movements with light and heavy weights. Specificity was high, although correlations were made for attenuation.  相似文献   

8.
Abstract

The leg strength of 70 college men was measured in a position designed to involve the power thrust of the major muscle groups used in the vertical jump. The subjects then performed a modified Sargent jump that used no arm snap. Although the reliability of all measures was high, individual differences in the ratio of tested strength to body mass showed only a low and nonsignificant correlation with jumping performance. The results are interpreted to support the hypothesis that strength exerted against a dynamometer involves a different neuromotor pattern than strength exerted by the muscles during a movement. Tables of means, variabilities, and intercorrelations are included in the report.  相似文献   

9.
Abstract

Forearm flexion strength of 65 college men was measured at two distances from the elbow at each of three angles of the forearm. The speed of forearm flexion movement was measured through an arc of 85°. Ebel intraclass reliabilities for strength and speed were high, i.e., .95 to .99. The extremely low correlations between limb strength and speed of movement, which ranged from —.06 to .14, are in agreement with the majority of the low correlations reported in earlier studies. The findings of this study support the theory of specificity in that individual differences in the speed of a limb involving a single joint are predominantly independent of strength measures associated with that limb and joint.  相似文献   

10.
Abstract

The aim of this study was to determine the variations in substrate utilization between men and women matched for ventilatory threshold (T vent) during incremental arm cranking and leg cycling exercise at 70, 85, 100 and 115% of the mode-specific T vent. Recreationally active men (n = 12) and women (n = 10) with similar values for percentage of peak oxygen consumption at T vent participated in the study. Ventilatory equivalence, excess CO2 and modified V-slope methods were used concurrently to determine T vent. The participants performed 5 min of exercise at each of 70, 85, 100 and 115% T vent during both arm cranking and leg cycling exercise. The females were tested during the early follicular phase for all trials. A two-way mixed-design analysis of variance was performed to test for differences between the sexes. When carbohydrate and fat oxidation were expressed relative to total fat-free mass, carbohydrate oxidation during arm cranking and leg cycling was significantly higher in men than women at each percentage of T vent. In contrast, women showed significantly higher fat oxidation across intensities during both arm cranking and leg cycling. Our results suggest that when substrate utilization is expressed relative to total fat-free mass, women appear to maintain a higher rate of fat and lower rate of carbohydrate oxidation than men during both incremental arm cranking and leg cycling exercise relative to T vent.  相似文献   

11.
Abstract

Masculinity and femininity ratings were studied in relation to motor performance scores of college women. Arm strength, muscular explosive power, pure speed, and the Humiston Test of motor ability showed a significant positive relationship to andric ratings and a significant negative relationship to gynic ratings. Subjects were classified as being “above”, “at”, or “below” the established mean of the andric and gynic factors. Comparison of mean scores revealed those above the andric mean to be superior on tests of speed, arm strength, and motor ability. Those below the mean of the gynic factor were found to be superior on these same tests and on explosive power. The extent to which the physical expression of masculinity exceeded that of femininity was more highly related to performance scores than were either masculinity or femininity ratings alone.  相似文献   

12.
Abstract

The net speed of arm movement made in response to sounds of 45, 65 and 85 db. loudness was measured by chronoscope. Reaction time was excluded. Thirty-six college men were tested. In another experiment, the force of successive contractions of the forearm muscles in response to serial auditory stimuli spaced 5 sec. apart was measured by a recording dynamometer. In both experiments there was a balanced order of presenting the three stimulus intensities. In general, the louder sounds produced faster arm movements and stronger contractions of the muscles. In explanation, it is postulated that greater perceived stimulus intensity results in stronger excitation of the pyramidal tracts and consequently more forceful muscular contractions.  相似文献   

13.
Abstract

In this study, we determined the specificity of a low frequency taekwondo training programme on physical fitness levels in adolescent females who receive limited physical education instruction (i.e. 2 days per week). Major components of physical fitness assessed were: skeletal muscle fitness (hand grip strength, bent arm hang, standing long jump, and isokinetic strength), flexibility (sit-and-reach test), speed and agility (10 × 5-m shuttle run), and cardiovascular fitness ([Vdot]O 2max and 20-m shuttle run). Changes in body composition were also assessed (dual X-ray absorptiometry, DXA). Participants were divided into two groups, a taekwondo training group (n = 21), which trained 50 min a day, 2 days per week for 12 weeks, and a control group (n = 10). Taekwondo training improved isokinetic strength, standing long jump, and sit-and-reach performance. Body fat mass and percent body fat were reduced. No changes in grip strength, bent arm hang time, speed and agility, or cardiorespiratory fitness were observed. Results indicate that low frequency taekwondo training in adolescent females produces beneficial changes in skeletal muscle fitness, flexibility, and body composition in a relatively short period of time. Consequently, this specific type of training can be useful to female adolescents in structured school environments where physical education classes are limited and there is little free time for physical activity.  相似文献   

14.
Abstract

The purpose of this study was to ascertain and to analyze the attitudes of men and women undergraduate students at the University of California, Santa Barbara, concerning the desirability of intensive athletic competition for girls and women. In January 1966, a questionnaire and an attitude inventory were administered to a random stratified sample of 300 undergraduate students. The attitude inventory consisted of 38 statements which were divided into four categories— social-cultural, mental-emotional, physical, and personality. Two hundred and eighty-four questionnaires and attitude inventories (94.7 percent) were completed and were submitted to statistical analysis.

Although the population was found to be favorable in attitude, the range of scores indicated that considerable differences of opinion existed concerning the desirability of athletic competition for girls and women.  相似文献   

15.
Abstract

As opposed to many other track-and-field events, marathon performances still improve. We choose to better describe the reasons for such a progression. The 100 best marathon runners archived from January 1990 to December 2011 for men and from January 1996 to December 2011 for women were analysed. We determined the impact of historical, demographic, physiological, seasonal and environmental factors. Performances in marathons improve at every level of performance (deciles). In 2011, 94% of the 100 best men athletes were African runners; among women athletes they were 52%. Morphological indicators (stature, body mass and Body Mass Index (BMI)) have decreased. We show a parabolic function between BMI and running speed. The seasonal distribution has two peaks, in spring (weeks 14 to 17) and autumn (weeks 41 to 44). During both periods, the average temperature of the host cities varies close to optimal value for long distance race. African men and women runners are increasingly dominating the marathon and pushing its record, through optimal eco-physiological conditions.  相似文献   

16.
Abstract

In this study we compared the kinematic features of the throwing motion between young baseball players of different age groups. Forty‐four Japanese baseball players aged 6.1 to 12.3 years who regularly played baseball, including pitchers and position players, had their throwing actions analyzed three‐dimensionally using high speed videography. Of this sample, 26 players aged above 9 years of age were categorized as the senior group, while the remaining 18 were categorized as the junior group. Senior group throwers had greater height and body mass, and produced a greater ball speed than junior group throwers. The throwing arm movement of senior group throwers was similar to that of adult skilled players. However, in the junior group throwers, the shoulder horizontal adduction angle was larger during the arm acceleration phase, and the maximum angular velocities of elbow extension and shoulder internal rotation occurred later than in senior group throwers. These results indicate that players aged above 9 years can acquire a mature throwing arm movement, while players younger than that will use an immature motion. A possible reason why these differences were shown is that the official baseball is relatively heavy for junior group throwers; they would be better advised to use a lighter ball in throwing practice.  相似文献   

17.
The purpose of this study was to examine gender differences in upper and lower body strength as a function of lean body weight and the distribution of muscle and subcutaneous fat in the upper and lower limbs. The subjects were 103 physically active men (n = 48) and women (n = 55). The peak torques produced during shoulder flexion (SF) and knee extension (KE) were used as measures of upper body and lower body strength, respectively. Flexed arm girth, thigh girth, triceps skinfold, and thigh skinfold were used to estimate the distribution of muscle and subcutaneous fat in the limbs. Results of the MANOVA revealed that the overall strength of men was significantly greater than that of women. Results of MANCOVA indicated that the SF and KE strength of women and men did not differ significantly when differences in lean body weight, arm girth, thigh girth, triceps skinfold and thigh skinfold were statistically controlled. High levels of SF and KE strength were associated with a high lean body weight and a large arm girth. Results of the multiple regression analysis indicated that for men a substantial portion of the variance in both SF and KE strength was explained by lean body weight alone; whereas strength variations in women were explained more adequately by including limb variables along with lean body weight. Within the limitations of this study, it was concluded that gender differences in upper and lower body strength are a function of differences in lean body weight and the distribution of muscle and subcutaneous fat in the body segments. Upper body strength is relatively more important than lower body strength in characterizing the gender difference in strength.  相似文献   

18.
Abstract

Pre- and post-season subcutaneous fat, girth and weight measures were made on 12 women varsity field hockey players and 17 women varsity basketball players at The Pennsylvania State University. Each experimental period consisted of eight weeks. Skinfold measures were taken with Lange calipers using the technique suggested by Keys. Girth measurements were made using a Tip Top Whyteface tape with a Gulick handle to aid in exerting equal tension on the tape for each measure. The sites measured were: (1) the right upper arm, (2) above the right iliac crest in the midaxillary line, (3) immediately to the right of and directly opposite the umbilicus, and (4) the anterior upper quarter of the right thigh in the midline. All sites were marked so that the girth measurements could be taken over the same place. Reliability was computed for all measures. Results of a comparison of pre- and post- mean scores indicated that the field hockey players studied showed a decrease in fat at the arm, umbilical, and thigh sites, with a reduction in girth at the umbilical site. Basketball players decreased in fat at the arm, iliac, and umbilical sites, with a reduction in girth of the thighs.  相似文献   

19.
Abstract

The incidence of orthopedic problems was examined in 5, 582 men and women who attended the Cooper Clinic in Dallas, Texas between 1974 and 1982. The effects of age, physical activity, physical fitness, and body mass index (EMI) on the occurrence of these problems were examined using a proportional hazards approach. The expected risk of orthopedic problems per person-year was 0.045 for men and 0.046 for women. For men, physical fitness, BMI, and physical activity were associated with orthopedic problems, while for women, physical activity was the main predictor. Age was not a factor for either gender. The effect of change in physical fitness, physical activity, and BMI was examined in a subset of 2, 325 persons with more than one visit to the clinic. For women, physical activity and a decrease in BMI were associated with orthopedic problems, while for men none of those factors were significant. Again, age was not a factor in either group. The absence of any age effect on the occurrence of problems suggests that with regard to orthopedic problems, moderate amounts of physical activity in generally healthy persons may be recommended without special consideration as to age.  相似文献   

20.
Abstract

Purpose: To investigate if combined strength and aerobic training can enhance aerobic capacity in the elderly to a similar extent as aerobic training alone when training duration is matched. Methods: Elderly men and women (age 63.2?±?4.7) were randomized into two intervention groups: an aerobic group (AG, n?=?17) and a combined group (CG, n?=?16). Subjects trained 40?minutes three times a week for 12 weeks. Both groups trained 20 minutes at 65% of heart rate reserve on ergometer cycles followed by another 20 minutes on the ergometer cycles for AG and 20-minute strength training for the lower body for CG. The primary outcome was VO2max. Secondary outcomes were maximal voluntary contraction (MVC) in isometric knee extension, 1 repetition maximum in three leg exercises, body fat, waist-to-hip ratio, blood pressure and score on the Health Survey Short Form 36 (SF-36). Results: Both groups improved VO2max (p?<?.01) and MVC (p?<?.001). VO2max increased 17% confidence interval (CI) [7.4–26] in CG and 26% CI [14.1–38.2] in AG, with no significant difference between groups. MVC increased 22% CI [16.3–27.7] in CG and 9% CI [4.6–13.5] in AG with CG improving MVC more than AG (p?<?.01). CG's score on the general health dimension on the SF-36 health survey improved more than AG's score. Conclusion: Elderly can substitute a part of their aerobic training with strength training and still improve VO2max to a clinically significant degree when strength training is performed with large muscle groups subsequently to the aerobic training. Combined training additionally improves strength and self-assessed general health more than aerobic training alone.  相似文献   

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