Studies in the Rate of Learning Gross Bodily Motor Skills

Abstract

The purpose of this investigation was to study the effect of varied amounts of milk in a balanced diet as it relates to short duration, sprint, and power types of athletic performance. Since milk contributes substantial amounts of protein to the diet, it was felt that protein might be a contributing factor in any cause and effect relationship between milk, diet, and physical performance. Hence protein at three levels were included as a variable by combining the three amounts with the changing levels of milk. Learning and conditioning tests were conducted before the start of the experiment and for the final three days of each diet period. Performance on the tests used in the study was not altered by the use of one or two quarts of milk per day in the diet as compared to the absence of all milk from the diet. At the different levels of protein used in this study, performance was unchanged.     

Using Sensewear armband and diet journal to promote adolescents' energy balance knowledge and motivation

PurposeEducating adolescents about energy balance (EB) is essential for effective weight control. This study utilized the Sensewear (SWA) armband and a diet journal to promote adolescents' EB knowledge and motivation.MethodsNinety sixth graders were randomly assigned into the experimental group (n = 46) who utilized SWA and diet journal for 7 consecutive days or the control group (n = 44) who did not. Both groups were pre- and post-measured on EB knowledge, situational interest, and weight. The experimental group was tracked on motivation effort, energy expenditure (EE), and energy intake (EI).ResultsEB knowledge significantly increased and situational interest remained stable (except for total interest and enjoyment) over time, but these changes did not favor the experimental group. Situational interest and motivation effort were correlated with EE, EI, and/or EB.ConclusionTracking EB using the SWA and diet journal is motivating but has limited efficacy in promoting adolescents' EB knowledge. Using these two tools as educational technology in conjunction with a focused, systematic, and educational approach has the potential to leverage adolescents' EB knowledge, motivation, as well as behaviors for living an energy-balanced lifestyle.     

Effects of Exercise and Milk Consumption on Blood Serum Cholesterol in Rats

Abstract

This study investigated the effects of exercise on blood cholesterol and correlated those effects with estimates of body fat through experiments with 45 albino weanling rats (15 litter mate trios). The rats were confined to individual cages in a temperature-controlled room and fed a stock diet until they were 11 weeks old. At this time the trios were divided. Group A was continued on a stock diet and exercised for an hour in the morning and an hour in the afternoon by forced swimming. Group B was subjected to the same exercise but a portion of the stock diet was replaced with powdered whole milk, so that 30 percent of the caloric intake was derived from the whole milk supplement. Group C was fed the stock diet but activity was restricted. After 15 weeks blood samples were taken, the animals sacrificed, and the heart and adrenals weighed. The specific gravity of the carcass was also determined. Exercise resulted in a statistically significant decrease in total and free blood serum cholesterol concentration. These animals were also leaner and had larger hearts and adrenal glands. Serum cholesterol was negatively related to carcass specific gravity. The milk supplement had no significant effect on any of these measures. Several possible explanations for the effects of exercise on blood cholesterol are discussed.     

Exercise training and antioxidant supplementation independently improve cognitive function in adult male and female GFAP-APOE mice

PurposeThe purpose of this study was to determine if antioxidant supplementation, moderate exercise, and the combination of both treatments could ameliorate cognitive performance in adult mice and whether the apolipoprotein E (APOE) genotype as well as sex could influence the functional outcomes of the treatments.MethodsFor a period of 16 weeks, separate groups of male and female mice expressing either the human APOE3 or APOE4 isoforms were fed either a control diet (NIH-31) or the control diet supplemented with vitamins E and C (1.12 IU/g diet α-tocopheryl acetate and 1.65 mg/g ascorbic acid). The mice were further separated into a sedentary group or a group that followed a daily exercise regimen. After 8 weeks on the treatments, the mice were administered a battery of functional tests including tests to measure cognitive and affective function.ResultsThere was no effect of genotype or treatment on the learning performance in the Morris water maze. In the discriminated avoidance task, APOE4 mice performed better in learning the discrimination component of the task. Overall, exercise improved performance of APOE4 and APOE3 mice on various aspects of the active avoidance task. Antioxidant supplementation improved performance only in the APOE4 mice. On the test for anxiety, APOE4 mice spent more time in the open arms and supplementation with antioxidant reversed that effect.ConclusionExercise was the most effective treatment at improving cognitive function in both genotypes and sex, while antioxidants seemed to be effective only in the APOE4. In young adult mice only non-spatial learning and memory were improved. The combination of the two treatments did not yield further improvement in cognition, and there was no antagonistic action of the antioxidant supplementation on the beneficial effects of exercise.     

Coach Selections and the Relative Age Effect in Male Youth Ice Hockey

Relative age effects (RAEs; when relatively older children possess participation and performance advantages over relatively younger children) are frequent in male team sports. One possible explanation is that coaches select players based on physical attributes, which are more likely witnessed in relatively older athletes. Purpose: To determine if coach selections are responsible for RAEs by comparing RAEs in male players who played competitive versus noncompetitive ice hockey. Method: Using chi-square, we analyzed the birth dates of 147,991 male ice hockey players who were 5 to 17 years old. Players' birth dates were divided into four quartiles, beginning with January to March, which coincides with Hockey Canada's selection year. Results: There were strong RAEs (p < .001) when players were selected to competitive teams by coaches through a tryout system. On noncompetitive teams that did not have coach selections, there were strong RAEs (p < .001) from 5 to 8 years old, but not 9 to 17 years old. Conclusions: Although coaches might perpetuate RAEs, other influential social agents might include parents, which ought to be investigated in future research.     

Event-specific impact test protocol for ice hockey goaltender masks

ABSTRACT

Goaltenders in the sport of ice hockey are at high risk for concussions from falls to the ice, player collisions and puck impacts. However, current methods used to certify helmets only consider head accelerations for drop tests which may not describe all common injury mechanisms relating to concussion. The purpose of this study was to describe the characteristics of 3 events associated with concussions for ice hockey goaltenders. A helmeted medium National Operating Committee on Standards for Athletic Equipment (NOCSAE) headform was impacted under conditions representing 3 injury events. Three impact locations’ velocities were selected for each event based on video analysis of real-world concussive events. Peak resultant linear acceleration, rotational acceleration and rotational velocity of the headform were measured. The University College Dublin Brain Trauma Model (UCDBTM) was used to calculate maximum principal strain (MPS) and von Mises stress in the cerebrum. Each impact event produced a unique dynamic response and brain stress and strain values. This demonstrates that a single impact event (i.e. falls) cannot adequately describe all impact events. As a result, impact protocols which assess multiple impact events such as the protocol described in this study should be used to evaluate ice hockey goaltender masks.     

Detailed description of Division I ice hockey concussions: Findings from the NCAA and Department of Defense CARE Consortium

Objective:Since concussion is the most common injury in ice hockey,the objective of the current study was to elucidate risk factors,specific mechanisms,and clinical presentations of concussion in men’s and women’s ice hockey.Methods:Ice hockey players from 5 institutions participating in the Concussion Assessment,Research,and Education Consortium were eligible for the current study.Participants who sustained a concussion outside of this sport were excluded.There were 332(250 males,82 females)athletes who participated in ice hockey,and 47(36 males,11 females)who sustained a concussion.Results:Previous concussion(odds ratio(OR)=2.00;95%confidence interval(95%CI):1.02‒3.91)was associated with increased incident concussion odds,while wearing a mouthguard was protective against incident concussion(OR=0.43;95%CI:0.22‒0.85).Overall,concussion mechanisms did not significantly differ between sexes.There were specific differences in how concussions presented clinically across male and female ice hockey players,however.Females(9.09%)were less likely than males(41.67%)to have a delayed symptom onset(p=0.045).Additionally,females took significantly longer to reach asymptomatic(p=0.015)and return-to-play clearance(p=0.005).Within the first 2 weeks post-concussion,86.11%of males reached asymptomatic,while only 45.50%of females reached the same phase of recovery.Most males(91.67%)were cleared for return to play within 3 weeks of their concussion,compared to less than half(45.50%)of females.Conclusion:The current study proposes possible risk factors,mechanisms,and clinical profiles to be validated in future concussions studies with larger female sample sizes.Understanding specific risk factors,concussion mechanisms,and clinical profiles of concussion in collegiate ice hockey may generate ideas for future concussion prevention or intervention studies.     

Physical activity levels,game performance and friendship goals using two different pedagogical models: Sport Education and Direct Instruction

Background: Advances in technology have changed children’s lifestyle so much that the majority of them do not meet the recommended 60 min of moderate to vigorous physical activity every day. Compulsory Physical Education has been highlighted as an ideal context to achieve the suggested physical activity (PA) goals, since it could be the only place where some students become truly physically active. In those classes, the teacher selects a pedagogical approach and this selection could be vital to meet the advised PA levels.

Purpose: The goal was to assess the effects of two instructional approaches, Sport Education Model (SEM) and Direct Instruction (DI) in Primary Education students’ physical activity intensity levels, game performance, and friendship goals.

Method: A total of 88 students with an average age of 11.16?±?0.63 years, enrolled in two year-5 (from 10 to11 years) and two year-6 (from 11 to 12 years) Physical Education classes of the same school agreed to participate. The number of participants in the SEM was 47 and in DI was 41. The schools’ administration distributed one class of each grade to the experimental group, which experienced SEM, and to the non-equivalent group, which experienced DI. The content selected for both study groups was the same: Handball. Both study groups experienced a 15-session learning unit (45 min per class, three sessions per week). The goal was to conduct the experiment in a non-manipulated (intact) educational context. It followed a pre-test, post-test, experimental, non-equivalent group design. Participants wore Actigraph GT3X accelerometers in order to monitor physical activity levels, answered questionnaires to assess friendship goals, and their game performance was assessed using the Game Performance Assessment instrument (GPAI).

Results: Results showed that students who experienced the SEM had significantly higher light and moderate physical activity levels, friendship-approach and friendship-avoidance goals, while the ones who experienced DI had significantly higher sedentary physical activity levels. The GPAI scores showed significant gains in students’ game performance in both study groups, but these were larger in the SEM one.

Conclusions: The SEM could be considered more effective than DI to improve Primary Education students’ PA levels, game performance and friendship goals.     

Diet and Physical Activity Patterns of Obese and Nonobese Elementary School Children

Abstract

The caloric intake and physical activity patterns of 50 fifth grade students were studied to determine the relative contributions of diet and physical inactivity in the development of obesity. On the basis of tricep skinfold measurements, the subjects were divided into four groups or levels of obesity. Seven-day diet recall records were then obtained with the cooperation of the children's parents. Activity patterns were studied by filming the subjects during games of high and low organization and during free play. Indexes of the duration and intensity of activity were derived from the film analysis. The caloric intake and physical activity patterns of the four groups were compared by the Duncan Multiple Range Test. Using the combined scores for all groups, correlation coefficients were computed to determine the relationship between (1) skinfold measures and total caloric intake, (2) skinfold measures and activity patterns, and (3) total caloric intake and activity patterns. The relative inactivity of the obese children and the relatively similar diets of all children regardless of body fat, as well as the significant negative relationship between activity indexes and body fat tended to support the contention that inactivity may be as important or more important than excessive caloric intake in the development and maintenance of childhood obesity.     

Redox status and antioxidant response in professional cyclists during training

Abstract

The aim of this study was to investigate whether different phases of training affect oxidative stress and antioxidant defences in professional cyclists. Ten professional cyclists, aged 21.8 ± 2.5 years, were enrolled in the study. They were classified into two groups of five athletes each one with similar nutritional intake excepting for the overload of vitamin C (1000 mg day^?1) and E (400 mg day^?1) supplementation in one of them. The cyclists of both groups performed the same exercise design, consisting of hard, tapering and recovery training periods. Total antioxidant capacity (TAC) of the diet, plasma oxygen radical absorption capacity (ORAC), lipid peroxidation (LPO), DNA damage (8-OHdG) and erythrocyte glutathione disulfide/glutathione ratio (GSSG:GSH^?1) were measured. During the intense exercise trainings, the cyclists without vitamin supplements had the TAC of diet significantly lower than the supplemented group. Plasma ORAC, LPO and 8-OHdG were similar in both groups of athletes. Athletes with supplements had a basal LPO:ORAC^?1 ratio lower than that without supplements, but this ratio converged to the same level at the end of the training in both groups of cyclists. Both groups of cyclists showed similar changes in GSSG:GSH^?1 ratio and in GSSG and GSH levels along the study. The data suggest that well-trained athletes with suitable ultra-endurance training volume and intensity do not require antioxidant vitamin supplements to adapt their endogenous antioxidant defenses to exercise-induced ROS.     

Trunk bend and twist coordination is affected by low back pain status during running

Abstract

Recent literature has related differences in pelvis–trunk coordination to low back pain (LBP) status. In addition, repetitive motions involving bending and twisting have been linked to high incidence of LBP. The purpose of this study was to examine trunk sagittal motion – axial rotation (‘bend and twist’) coordination during locomotion in three groups of runners classified by LBP status (LBP: current low back pain; RES: resolved low back pain and CTR: control group with no history of LBP). Trunk kinematic data were collected as running speed was systematically increased on a treadmill. Within-segment coordination between trunk sagittal and transverse planes of motion (trunk lean and axial rotation, respectively) was calculated using continuous relative phase (CRP), and coordination variability was defined as the between stride cycle standard deviation of CRP (CRPvar). Bend–twist coordination was more in-phase for the LBP group than CTR (p = 0.010) regardless of running speed. No differences in CRPvar were found between the groups. The results from our coordination (CRP) analysis were sensitive to LBP status and suggest that multi-plane interactions of the trunk should be considered in the assessment of LBP. This analysis also has potential for athletically oriented tasks that involve multi-plane interactions of the trunk, particularly ones that contain asymmetric action, such as sweep rowing or a shot on goal in field hockey or ice hockey.     

Motor Skill and Behavior Adjustment: An Exploratory Study

Abstract

This study was undertaken to evaluate the effectiveness of a supplementary physical education program in improving selected motor skills and behavior adjustment of primary school children who were poor in motor skills and deficient in behavior adjustment. Tests were administered to members of two experimental groups (instruction and non-instruction) and two control groups (deviant and normal) at various times during a one-year period. Improvement in motor performance demonstrated by each of the two experimental groups was significantly greater than such improvement made by each of the control groups. The level of motor performance attained by each of the experimental groups did not significantly differ from the level of motor performance exhibited by normal primary school children. Changes in behavior adjustment among the participants were not statistically significant.     

Weight Transfer Patterns During the Golf Swing

Abstract

Twenty right-handed male golfers participated as subjects in an investigation of the two-dimensional weight transfer pattern produced during the golf swing. Ten subjects possessed handicaps of less than 10 strokes while the remaining 10 subjects had handicaps greater than 20. Center of vertical force locations were sampled during the swing with a computerized forceplate at a rate of 350 Hz. The occurrence of the initiation of the downswing (TOS) was monitored by a vacuum transducer in the club grip while ball contact (CON) was monitored by a laser/photocell system. Variables analyzed consisted of minimum/maximum force distribution ratios from heel to toe and from back foot to target foot as well as distribution ratios at TOS and CON. Intraclass correlation coefficients showed all variables to be reliable for both groups (r > 0.8). A subsequent discriminant function analysis produced one significant function (p < .05) which served to distinguish between the low and high handicap groups. The accuracy of group membership predicted from weight transfer patterns was 85%.     

Effects of Two Systems of Weight Training on Circulorespiratory Endurance and Related Physiological Factors

Abstract

Three groups, two experimental and one control, consisting of 20 college freshmen in each group, were tested doing moderate and all-out exercise on a bicycle ergometer. Selected physiological responses and the circulorespiratory endurance times were measured. An eight-week training period followed during which the experimental groups participated in weight-training programs and the control subjects in archery or bait casting. After training, the tests were again administered.

Though there was an indication of improved circulorespiratory responses by the weight-training groups following training, statistical treatment of the data revealed no significant differences among the three groups in their responses to exercise.     

Regular moderate aerobic exercise improves high-fat diet-induced nonalcoholic fatty liver disease via monoacylglycerol O-acyltransferase 1 pathway suppression

PurposeMonoacylglycerol O-acyltransferase 1 (MGAT1) is reported to play a key role in the development of diet-induced nonalcoholic fatty liver disease (NAFLD). Thus, this study investigated the effect of exercise on suppression of the MGAT1 pathway in NAFLD tissue of high-fat diet (HFD)-induced obese rats.MethodsMale Sprague-Dawley rats were fed an HFD containing 45% fat for 6 weeks. Upon confirmation that NAFLD had been induced in the obese animals, they were divided into HFD-fed groups provided with exercise (HFD + EXE) or without exercise (HFD) and a group given dietary adjustment (DA) only, for a further 6 weeks of intervention treatment. The 6-week regular moderate aerobic exercise consisted of an accommodation phase with increasing exercise. Lipid accumulation in the liver tissue was determined by Oil Red O staining. The MGAT1 and liver lipogenic gene mRNA levels were measured by qPCR, and their protein levels by western blot assay.ResultsOil Red O staining showed that NAFLD was successfully induced by HFD-fed. The gene expression of MGAT1 was significantly lower in HFD + EXE than HFD. However, there was no significant difference between HFD + EXE and DA. The protein expression of MGAT1 was significantly lower in HFD + EXE than both HFD and DA. Messenger RNA and protein expression of other lipogenic genes were not different among groups. These data indicate that exercise suppresses MGAT1 pathway regardless of HFD feeding; in part, this effect could be greater than DA.ConclusionOur data suggest that exercise can improve NAFLD, which is probably due to suppression of MGAT1 pathway.     

A Comparison of Heart Rate Responses in Females by Player Position in Standard and Zoneless Ringette

Abstract

The purpose of this study was to examine the relationship between game heart rates by player position during two types of ringette rules: standard rules and experimental rules which did not include zone restrictions (zoneless). Two hundred twenty-five female ringette players (104 standard rules and 121 zoneless rules) were monitored during regular league and tournament play during the 1985 ringette season. This included over 50 games, approximately half played under each set of rules; and included at least five games played in each of five age categories. Field measurement of the game heart rates was conducted by use of an EST Sport-Tester heart rate monitor, which recorded the average of each 30 s heart rate profile. An analysis of variance (ANOVA) with repeated measures was performed to determine the significance of the difference by player position and rules in the mean peak heart rates for six shifts on the ice, the first three and the last three. There were significant differences (p < .05) between mean peak heart rates for forwards and defenders between standard and zoneless rules, but there were no differences between centers. Significance tests were also conducted by position and age division, and the differences in the heart rates of the defenders were significant in the junior belles (13–14) and belles (15–17) age divisions.     

Differential Learning as a Key Training Approach to Improve Creative and Tactical Behavior in Soccer

Purpose: The aim of this study was to identify the effects of a differential-learning program, embedded in small-sided games, on the creative and tactical behavior of youth soccer players. Forty players from under-13 (U13) and under-15 (U15) were allocated into control and experimental groups and were tested using a randomized pretest to posttest design using small-sided games situations. Method: The experimental group participated in a 5-month differential-learning program embodied in small-sided games situations, while the control group participated in a typical small-sided games training program. In-game creativity was assessed through notational analyses of the creative components, and the players’ positional data were used to compute tactical-derived variables. Results: The findings suggested that differential learning facilitated the development of creative components, mainly concerning attempts (U13, small; U15, small), versatility (U13, moderate; U15, small), and originality (U13, unclear; U15, small) of players’ actions. Likewise, the differential-learning approach provided a decrease in fails during the game in both experimental groups (moderate). Moreover, differential learning seemed to favor regularity in pitch-positioning behavior for the distance between players’ dyads (U13, small; U15, small), the distance to the team target (U13, moderate; U15, small), and the distance to the opponent target (U13, moderate; U15, small). Conclusions: The differential-learning program stressed creative and positional behavior in both age groups with a distinct magnitude of effects, with the U13 players demonstrating higher improvements over the U15 players. Overall, these findings confirmed that the technical variability promoted by differential learning nurtures regularity of positioning behavior.     

A Multidimensional Timing Device for Cinematography

Abstract

Six tests were developed for the purpose of measuring selected basic skills in ice hockey. The test-retest method indicated four tests as reliable. Validity coefficients for each of the four tests when compared to subjective ranking in each skill ranged from .75 to .96. Intercorrelations were computed among the tests. The puck carry test correlated with the other three tests and was determined the best single-item for measuring overall ability. It was concluded that an ice hockey test battery should include at least three of the tests.     

体育教学中防控近视的睫状肌训练频次研究

目的： 分析比较体育教学中低频15次、中频30次,以及高频60次的睫状肌训练对八年级学生视力所产生的不同影响方法： 在体育课中分别对3个实验组进行低频15次、中频30次、高频60次睫状肌训练,测量并分析干预前后实验组与对照组学生的裸眼远视力与动态视力结果： (1)低频15次组学生的裸眼远视力与动态视力无显著性变化;(2)中频30次组学生的动态视力在干预后显著上升,裸眼远视力的提高无显著性差异;(3)高频60次组学生的裸眼远视力与动态视力在干预后均显著上升;(4)对照组学生的裸眼远视力与动态视力呈下降趋势结论： 体育教学中嵌入不同频次的睫状肌训练对八年级学生视力水平的影响不同,其中60次高频训练对裸眼远视力改善效果最佳,30次中频训练对动态视力的改善效果更好,15次低频训练能够基本维持学生裸眼远视力和动态视力的原有水平。在体育教学中进行睫状肌训练能够有效延缓近视的发展速度,促进学生视力水平发展。     

The effect of glycaemic index of high carbohydrate diets consumed over 5 days on exercise energy metabolism and running capacity in males

Abstract

The aim of this study was to determine whether rates of total fat and carbohydrate oxidation and endurance capacity during running conducted in the fasted state are influenced by the glycaemic index (GI) of high carbohydrate diets consumed over 5 days. Nine healthy males performed three treadmill runs to exhaustion at 65% of maximum oxygen uptake ([Vdot]O_2max): after a habitual diet (control trial), after 5 days on a high carbohydrate/high glycaemic index diet, and after 5 days on a high carbohydrate/low glycaemic index diet in randomized counterbalanced order. No significant differences in rates of fat and carbohydrate oxidation, concentrations of plasma insulin, glucose, non-esterified fatty acids and glycerol, or time to exhaustion were observed between the high carbohydrate/high glycaemic index and high carbohydrate/low glycaemic index trials. Compared with the control trial, the concentration of plasma glycerol and rate of fat oxidation were lower (P < 0.05) and the rate of carbohydrate oxidation higher (P < 0.05) in both the high carbohydrate/high glycaemic index diet and high carbohydrate/low glycaemic index trials during the run to exhaustion. In conclusion, the extent by which a high carbohydrate diet consumed over 5 days reduces rate of fat oxidation during subsequent running exercise in the fasted state is not influenced by the glycaemic index of the diet.