Healthy Male University Students Research Articles

Is There A Relationship Between the Functional Reach Test and Flexibility?

This study examined the influence of short-term stretching and improved flexibility on functional reach (FR) performances (reach distance and rotation angle of various joints during reaching). 17 healthy male university students were assigned to either experimental and control groups based on the random assignment. A pre-test/Post-test design was used in this study. The variable factor for the experimental group was stretching (jogging for warming up and stretching). Main outcome measures were flexibility (static maximum range of motion of shoulder, hip, and ankle joints) and FR of participants. FR test performances were assessed by the reach distance and rotation angles of each joint during reaching. No significant differences between the groups were found in the participants’ characteristics, and no skeletal muscle fatigue was found in the lower limb. In the experimental group, shoulder and hip-joint flexibility increased significantly by stretching, and showed higher values than that of the control group. In contrast, FR test performance did not reveal any changes. Slight intraindividual ROM improvements by short-term stretching may be less important for FR postural strategies. FR test performances are little influenced by light static stretching in young healthy adults.

Effect of Garment Pressure on Lower Limb Muscle Activity during Running

Recently, it has been reported that suitable garment pressure contributes to accelerating human blood circulation, improving sports performance and alleviating sports fatigue. In this study, effect of pressure exerted by knee-high gradient compression socks (GCS) on the lower limb muscles was investigated. Two healthy male college students volunteered to participate in this study. They were asked to run on a treadmill at a speed of 10 km/h with a GCS worn on one leg and a usual sports sock worn on the other leg until being tired out. During running, the surface electromyography (sEMG) of two lower limb muscles —— gastrocnemius medialis of the right leg (R-GM) and the left leg (L-GM) was recorded simultaneously. It was found that: pressure exerted on the lower limb by GCS gradually decreased from ankle to below-knee; GCS pressure helped to reduce muscle oscillation; wearing GCS seemed to help to reduce muscle fatigue during running.

수직점프 시 스포츠 테이핑이 하지의 운동학적 변인에 미치는 영향

The purpose of this study was to evaluate the effect of taping-tape with or without using spiral taping on vertical jump. The subjects for this study were about 20 years old healthy male college students without muscloskeletal diseases. Data for EMG activity and Ground Reaction Force(GRF) were estimated at three knee angles(i.e., 45, 90 & full degree). As a result, there was no statistical significance in max GRF at 90 and full degree regardless of spiral taping-tape. On the other hand, statistical significance was found when vertically jumping at 45 degree knee angle(p<.05). All the data for EMG activity at the three knee angles were not statistically significant, but there was a trend for a decrease in average EMG activity in elector spinae & Medial gastrocnemius at 90 degree knee angle. Based on these data, initial flexor action of knee was stabilized with spiral taping-tape when vertically jumping, resulting in improved muscular activity in Medial gastrocnemius. In conclusion, taping technique for jumping ability associated muscles like quadriceps is also required to develop.

Levels of awakening salivary CgA in response to stress in healthy subjects

To determine the changes in salivary chromogranin A (CgA) levels upon awakening in response to of stress by investigating the relationship between salivary CgA levels and the stress response as assessed by GHQ-28 tests. The study cohort comprised 40 healthy male university students (age range 19-22 years). Salivary CgA levels were measured at 7:00 a.m. (awakening) and at 7:30, 8:00, and 8:30 a.m. (after awakening). The salivary CgA level was 0.91 ± 0.20 and 0.42 ± 0.1 pmol/ml at 7:00 a.m. in students scoring low (n = 26) and high (n = 14), respectively, on the "severe depression" subscale. This difference in salivary CgA levels at 7:00 between high and low scorers was statistically significant (p < 0.05). Our findings indicate that depression may influence secretions of salivary CgA via chronic stress-related attenuation of the sympathetic-adrenomedullary system activity.

Comparative Effects of 6-Week Balance, gluteus Medius Strength, and Combined Programs on Dynamic Postural Control

There are few outcomes-based studies that address hip strategy and gluteus medius strength (GMS) for maintaining dynamic postural control. To determine whether GMS training, proprioception training, or a combination of the 2 has an effect on dynamic postural control. Pretest-posttest, repeated measures. Sports-medicine clinic. 48 healthy male and female college students obtained via sample of convenience. Three 6-wk programs including exercises for proprioception, GMS, and combined. Eight Star Excursion Balance Test (SEBT) reach distances and GMS for the dominant leg. There was no significant difference between groups. The combination group demonstrated the most improvements in SEBT reach distances, whereas the GMS group demonstrated the most improvement in GMS. Use of exercises for proprioception, GMS, or a combination of the 2 will help improve dynamic postural control in healthy, active individuals.

비대칭적 입식자세에서 상지 조립 작업 시 체간 및 둔부 근육의 좌우 근활성도 비교

The purpose of this study was to compare the electromyographic(EMG) activities of trunk and hip muscles between right and left sides while subjects performed prolonged manual task in asymmetric and symmetric weight-bearing posture. Fifteen healthy male college students were recruited for this study. The subjects were asked to perform bimanual upper extremity task for 6 minutes in two different standing postures. In the symmetric weight-bearing posture, the subjects were standing with evenly distributed body weights to both legs. In the asymmetric weight-bearing posture, the subjects distributed about 90% of their body weight onto their preferred(supporting) leg and 10% of their body weight onto the opposite leg while they were standing. EMG activities of the right and left internal oblique, erector spinae, gluteus maximus, and gluteus medius were measured and normalized as % MVIC. Then the EMG data were statistically analyzed using paired t-tests. The EMG activities of all measured muscles were not significantly different between the right and left side in the symmetrical weight-bearing posture(p>0.05). However, the EMG of the supporting side internal oblique was significantly lower than the opposite side(p<0.05), and the EMG of the erector spinae, gluteus maximus, and gluteus medius were significantly greater on the supporting side(p<0.05). The results of this study support that unbalanced use of right and left muscle possibly causes the changes in muscle length which results in asymmetry of trunk and hip muscles. Furthermore, the uneven weight support onto right and left legs will cause a distortion of viscoelastic ligaments around hip and sacroiliac joints in the long run. Further studies to determine the effect of various manual tasks on the trunk and hip muscles as well as the effect of asymmetrical weight-bearing standing posture on hip and back muscle fatigue may be required.

The Effects of Resistance Training with and without Trunk Stabilization Exercises on Cutting Mechanics

While trunk stabilization exercises or "core" training are often prescribed to improve performance and prevent injury, no conclusive evidence exists to quantitatively show that these types of training improve lower extremity biomechanics in ways that might reduce risk of ACL rupture. PURPOSE: To investigate the effects of trunk stabilization training on dynamic loading of the lower extremity during unanticipated cutting maneuvers in athletes. METHODS: Fifteen healthy male college students (age = 20.9 ± 1.0 yrs, height = 1818 ± 55 mm, mass = 84.6 ± 6.3 kg) who played football in high school with no previous history of ACL tear were recruited for the study. Subjects were randomly assigned to a 6-week resistance training (RT) program or a 6-week trunk stabilization (TS) program. RT participants performed 4 sets of bilateral resistance training with free weights for the upper and lower extremities during 3 1-hr sessions per week. TS participants performed the same resistance exercises but replaced the first set with trunk stabilization exercises. A pre-test/post-test design was used. All subjects performed a 45° unanticipated cutting maneuver task at pre- and post-testing. An opto-electronic motion capture system and 2 force plates were utilized for data collection. The Point Cluster Technique was used for measuring femur and tibia kinematics and inverse dynamics were used to estimate net external joint moments, which were normalized to weight and height [%BW*ht]. Three dominant leg trials were analyzed for external knee abduction and tibial internal rotation moments. The models were adjusted for speed and cut angle. RESULTS: No significant interactions in knee abduction moment (p=0.49) or tibial internal rotation moment (p=0.23) were observed from pre- to post-test for the intervention group (TS). CONCLUSION: This study found that trunk stabilization training had no effect on knee abduction or tibial internal rotation moments. Due to the small sample size, further research may be warranted to confirm these findings. Future studies investigating other training approaches to improve dynamic trunk control during functional activity may also provide additional insight into the relationships between trunk control and lower extremity cutting mechanics. Funded by NFL Charities Foundation

Analysis of Observation Characteristics by Cognitive Style : MEG Study

The purpose of this study is to analyze the ERF components patterns of observers who have different cognitive styles using magneto-encephalography (MEG). The task was developed based on the CSA (Cognitive Style Analysis) program. Eight right-handed, healthy male college students participated in voluntarily. To investigate college students' ERF components during the task, an MEG system with block design was used to measure magnetic signals in their brains. For examining the observation characteristic by cognitive style, MEG ERF components were analyzed. As a result, four ERF components (M1, M2, M3, M4) were observed. Through the results of this study, the reason for different observation characteristics by cognitive styles was verified in the neurophysiological methods. This study will have implications to establish theories on scientific observation and cognitive styles.

Response of salivary peroxidase to exercise intensity

Oral peroxidase, one of the most important salivary antioxidant enzymes, is subjected to alternation due to various body conditions. The aim of this study was to assess the effect of exercise intensity on salivary peroxidase activity. Using a randomized design, ten healthy male university students (mean age, 23.22; s (x) = 2.34 years) completed treadmill runs with initial velocity 6.73 km/h at the rate of 1.58 km/h increase every 3 min until exhaustion. Unstimulated whole saliva collected over a 5-min period in pre-weighed tubes before, immediately after exercise, and 1 h after exercise was analyzed for total protein and saliva peroxidase activity. The saliva flow rate ranged from 0.08 to 1.40 ml min(-1) at rest and was not significantly affected by the exercise. Peroxidase activity in each sample was measured using 4-amino antipyrine as substrate. In the incremental exhaustion run and also at 75% VO(2max), the secretion rates of peroxidase increased. No significant changes in saliva flow rate were observed in any treadmill run. Treadmill runs at 75% VO(2max) and to exhaustion increased the activity of peroxidase immediately after exercise which decreased after 1 h. It was concluded that short-duration, high-intensity exercise increases the activity rate of peroxidase despite no change in the saliva flow rate. These effects appear to be associated with changes in sympathetic activity and not the hypothalamic pituitary adrenal axis.

Post-Eccentric Exercise Blunted hGH Response

The purpose of the present study was to test if a previous acute concentric exercise bout blunts hGH response after an eccentric exercise bout. Nine healthy untrained male university students (25.4+/-0.5 yr, 176.5+/-1.2 cm, and 79.4+/-2.0 kg) performed a concentric exercise bout followed by an eccentric exercise bout one week later. Serum human growth hormone (hGH), creatine kinase (CK), and lactate were measured before, immediately and up to 32 h after both exercise bouts. Higher lactate values were observed immediately, 5 and 10 min after the concentric bout (70%, 119%, and 142%, respectively, p<0.05) than the eccentric bout. There was a CK main time effect at 8 and 32 h after the exercise bouts compared to baseline values (p<0.002). However, peak serum CK effect size was higher after the concentric than the eccentric exercise bout, 1.3 and 0.9, respectively. hGH increased after both exercise bouts, however it reached significance only at immediately (207%), 5 min (256%), 10 min (276%), 20 min (300%), and 40 min (168%) after the concentric exercise bout (p<0.05). Our findings suggest that a previous concentric exercise bout may blunt the anabolic response expected after an eccentric exercise bout.

Quantifying scapula orientation and its influence on maximal hand force capability and shoulder muscle activity

Background Non-neutral scapular orientations are often implicated as potential causes of shoulder pathologies. However, their specific influence on shoulder functional capabilities is largely unknown. This study objectively measured scapular orientation and quantified its influence on shoulder muscle activity levels and hand force capabilities during vertical and horizontal manual exertions. Methods Ten healthy male university students performed 24 exertions in combinations of scapular orientation (protracted, neutral and retracted), exertion direction (up, down, medial, lateral) and intensity (maximal or 40 N). Scapular orientation was quantified using an acromion marker cluster method. An orientation by intensity repeated measures ANOVA identified differences in quantified scapular orientation. A two-way multivariate ANOVA identified the influence of scapular orientation and hand force direction on muscle activity and hand force capability. Findings Participants assumed consistent retracted, neutral, and protracted scapular orientations during exertions, and these three orientations were different from each other ( F(2, 99) = 158.57; P-value: 0.0001). Scapular orientation and exertion direction influenced muscle recruitment almost universally ( P-value: 0.05). Scapular orientation did not influence hand force capability ( F(2, 99)=1.34; P-value: 0.05), but a hand force direction effect on force existed ( F(3, 99)=144.19; P-value: 0.0001). Interpretation These findings support recommendations of health practitioners who advocate neutral scapular orientations to reduce injury risk, as a neutral orientation achieved a balanced overall muscle use pattern between retraction and protraction. Also, lowered muscle activity and higher maximal forces suggest that downward exertion forces may be preferable when possible.

Stilt walking: How do we learn those first steps?

This study examined how young healthy adults learn stilt walking. Ten healthy male university students attended two sessions of testing held on two consecutive days. In each session participants performed three blocks of 10 stilt-walking trials. Angular movements of head and trunk and the spatial and temporal gait parameters were recorded. When walking on stilts young adults improved their gait velocity through modifications of step parameters while maintaining trunk movements close to that observed during normal over-ground walking. Participants improved their performance by increasing their step frequency and step length and reducing the double support percentage of the gait cycle. Stilts are often used for drywall installation, painting over-the-head areas and raising workers above the ground without the burden of erecting scaffolding. This research examines the locomotor adaptation as young healthy adults learn the complex motor task of stilt walking; a task that is frequently used in the construction industry.

Physiological responses to workload change. A test/retest examination

The purpose of this study is to examine the test/retest consistency of physiological responses induced by mental tasks. Fifteen healthy male university students were recruited as participants. They were instructed to perform a 5-min Multi-Attribute Task Battery (MATB) trial three times successively. The task difficulty level of the tracking task of the second trial was set as medium (M). The first one was set as more difficult (H) and the last trial was easiest (L). The difficulty levels of the other two tasks (resource management and system monitoring) of the MATB were identical for all three trials. The participants repeated this procedure on three different days separated by at least a 1-day interval. The order of the tasks was the same for all repeated trials, i.e., H–M–L. Tissue blood volume from the tip of the nose using a laser Doppler blood flow meter, skin potential level (SPL), ECG from three leads on the chest, systolic time intervals (pre-ejection period, left ventricular ejection time), and hemodynamic parameters (stroke volume, cardiac output) were recorded during the task trials and before and after 5-min resting periods. The participants reported their subjective workload via NASA-TLX after each task trial. Autonomic nervous system parameters derived from the above-mentioned signals, subjective workload scores, and performance indices of MATB were analyzed, and test/retest reliability was investigated. The results showed that a significant test/retest correlation was obtained for SPL for more participants than in the other parameters, although there were large individual differences.

Inter- and intra-individual variations of urinary endogenous metabolites in healthy male college students using 1H NMR spectroscopy

Most human metabolomics studies have shown that spectral outputs of (1)H nuclear magnetic resonance fingerprinting are strongly influenced by inter- and intra-individual variations; however, few studies have been performed to evaluate the inter- and intra-individual variations in urinary endogenous metabolites. We recruited 30 male college students to evaluate the factors affecting intra- and inter-individual variations in urinary endogenous metabolites. Statistical analysis for variations in urinary metabolites was performed after eliminating outliers found in principal component analysis (PCA) plots. Inter-individual variations were relatively low for 2-oxoglutarate, succinate, citrate, dimethylglycine, and taurine, but high for trimethylaminoxide (TMAO), hippurate, and lactate. Intra-individual variations for 2-oxoglutarate, citrate, dimethylglycine, and taurine were relatively low, but high for TMAO and hippurate. The factors affecting inter-individual variation of lactate were age, body mass index, beverages, and alcohol, whereas the factors affecting intra-individual variation of lactate were age and fish. Kim Chi intake affected the inter-individual variation of succinate, citrate, TMAO, and hippurate; however, it did not affect the intra-individual variation of endogenous metabolites. Our results showed that inter- and intra-individual variations in urinary endogenous metabolites were very large, and significant factors affecting inter- and intra-individual variation were diverse, even after eliminating outliers in PCA analysis.

Effect of Short-term Exposure to Whole Body Vibration in Humans: Relationship between Wakefulness Level and Vibration Frequencies

The purpose of this study was to clarify the influence of different vibration frequencies on wakefulness level. Subjects were 7 healthy male university students aged 21.9+/-1.6 years (mean). All students were non-smokers. Three exposure conditions were used (10 Hz vibration, 20 Hz vibration, and no vibration). Whole-body vertical vibration was applied to subjects sitting on a car passenger seat using a whole-body vibration shaker (CV-300, Akashi) at a single frequency (10 or 20 Hz) at an acceleration level of 0.3 ms(-2) r.m.s. for 24 min. The objective wakefulness level based on EEGs was evaluated in terms of the alpha attenuation coefficient (AAC) obtained by the Alpha Attenuation Test (AAT). As parameters of psychological stress, salivary 3-methoxy-4-hydroxyphenylglycol (MHPG) and homovanillic acid (HVA) were used. The subjective wakefulness level was evaluated using a questionnaire based on the Kwansei Gakuin Sleepiness Scale (KSS), which is a scale developed for the Japanese based on the Stanford Sleepiness Scale (SSS). The KSS score, representing the subjective wakefulness level, decreased after the exposure irrespective of the exposure condition, but the decrease was not significant. The AAC, representing the objective wakefulness level, significantly decreased only after vibration exposure (10 Hz/20 Hz) but did not differ between the two vibration frequencies. No significant changes were observed after exposure to whole-body vibration in MHPG or HVA as parameters of vibration-related stress. The AAC decreased after exposure to whole-body vibration (10 Hz/20 Hz), suggesting a decrease in the wakefulness level. However, no differences were observed in the influence of the two different vibration frequencies test.

最大負荷運動におけるヒト末梢血好中球の NADPH オキシダーゼ活性と細胞系スーパーオキシド生成能との関係

The purpose of this study was to examine reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity, - a generated superoxide - of neutrophils in human peripheral blood after maximal exercise. Ten healthy male college students (20.2 ± 0.4 yr, 170.5 ± 1.3 cm, 62.8 ± 1.9 kg) participated after giving written informed consent. They performed an incremental exercise to volitional exhaustion using a bicycle ergometer. Peripheral blood was collected before exercise (Pre), just after exercise (Post) and 1-hour after exercise (Post-1h). Phorbol 12-myristate 13-acetate (PMA)-stimulated and opsonaized zymosan (OZ)-stimulated superoxide-generating activity of neutrophils was measured by the cytochrome c reduction assay. NADPH oxidase activity was measured by a cell-free system. NADPH oxidase activity significantly decreased in Post-1h compared with Pre and Post. A similar tendency was seen in PMA-stimulated activity, but not in OZ-stimulated activity. A strong positive relationship between NADPH oxidase activity and PMA-stimulated activity was found in Pre and this relationship attenuated after exercise. NADPH oxidase activity was not related to OZ-stimulated activity at any time points. We concluded that NADPH oxidase activity decreased after exhaustive maximal exercise in human peripheral neutrophils, and suggest that PMA-stimulated activity, relatively - speaking, reflects NADPH oxidase activity; but OZ-stimulated activity is independent of NADPH oxidase activity.

The Acute Effects of Dynamic and Ballistic Stretching on Vertical Jump Height, Force, and Power

Stretching before performance is a common practice among athletes in hopes of increasing performance and reducing the risk of injury. However, cumulative results indicate a negative impact of static stretching and proprioceptive neuromuscular facilitation (PNF) on performance; thus, there is a need for evaluating other stretching strategies for effective warm-up. The purpose of this study was to compare the differences between two sets of ballistic stretching and two sets of a dynamic stretching routine on vertical jump performance. Twenty healthy male and female college students between the ages of 22 and 34 (24.8 +/- 3 years) volunteered to participate in this study. All subjects completed three individual testing sessions on three nonconsecutive days. On each day, the subjects completed one of three treatments (no stretch, ballistic stretch, and dynamic stretch). Intraclass reliability was determined using the data obtained from each subject. A paired samples t-test revealed no significant difference in jump height, force, or power when comparing no stretch with ballistic stretch. A significant difference was found on jump power when comparing no stretch with dynamic stretch, but no significant difference was found for jump height or force. Statistics showed a very high reliability when measuring jump height, force, and power using the Kistler Quattro Jump force plate. It seems that neither dynamic stretching nor ballistic stretching will result in an increase in vertical jump height or force. However, dynamic stretching elicited gains in jump power poststretch.

Thermal evaluation of a chair with fans as an individually controlled system

It is difficult for a total air-conditioning system to satisfy the thermal comfort of all workers in an office. Therefore, an individually controlled system that can create a comfortable thermal environment for each worker is needed. In the present study, two chairs incorporating two fans each, one under the seat and one behind the backrest, were developed to provide isothermal forced airflow to the chair occupant. The chairs differed in the size of the fans. Experiments were conducted in a climate chamber during the summer. Seven subjects, who were healthy male college students, were allowed to freely control the two built-in fans by adjusting dials on the accompanying desk. The room air temperatures were set at 26 °C, 28 °C, 30 °C and 32 °C. The following findings were obtained. At a room air temperature of 28 °C, the whole-body thermal sensations were almost thermally neutral, regardless of the type of chair. At a room air temperature of 30 °C, the occupants were able to create acceptable thermal environments from the viewpoints of whole-body thermal sensation and comfort by using the chairs with fans. Their local discomfort rates at the back and lower back, which were affected by the isothermal airflows, were greatly improved at this room air temperature. However, at a room air temperature of 32 °C, the chairs tested in the present study were not able to provide acceptable thermal environments. In order to provide a more comfortable environment to the chair occupants, additional local systems to cool the head, arms, and hands are needed.

Pupillary Response Induced by Acupuncture Stimulation – An Experimental Study

To investigate whether acupuncture stimulation affects autonomic nerve function by measuring pupil diameters with electronic pupillography. Two studies were conducted (Experiment 1 and 2) in the Tsukuba University of Technology, Tsukuba, Japan. Experiment 1 examined the responses before, during and after acupuncture. Experiment 2 compared acupuncture and a no acupuncture control in a two period, repeated measurement crossover design. Twelve healthy male university students were recruited for Experiment 1 and nine healthy male university students for Experiment 2. The intervention was superficial acupuncture at the acupuncture point TE5. Following the insertion, gentle repetitive tapping stimulation was applied during the subject's exhalation phase in a sitting position for 90 seconds. The main outcome measures in Experiment 1 were pupil diameter, heart rate, pulse wave and blood pressure. In both experiments, pupil diameter was measured for three minutes before acupuncture stimulation, during stimulation and for three minutes after stimulation. In Experiment 1, a decrease in pupil diameter was observed after acupuncture stimulation (P=0.018) and a decrease in heart rate was observed during the stimulation (P=0.049). Moreover, a significant decrease of pulse wave amplitude was observed during and after acupuncture stimulation. In Experiment 2, a decrease in pupil diameter occurred after acupuncture stimulation (P=0.007), whereas no change occurred under the no acupuncture control. It is thought that the pupillary constriction observed after gentle, superficial acupuncture stimulation may be attributed to an increase of parasympathetic nerve function. Further study is necessary in order to further clarify the duration of the observed response and to elucidate the mechanisms behind it.

The Effect of Open-Stance Cycling with Limited Ankle Movement on VMO and VL Ratio

Patellofemoral pain syndrome is a common knee problem. A lot of discussion about the cause of this syndrome has be proposed, e.g. increasing Q-angle, overuse, quadriceps weakness, VMO/VL imbalance. Cycling with special lower extremity positioning has been proposed as a VMO selective training method. PURPOSE: The purpose of this study was to compare the effect of different cycling methods on VMO and VL activation. METHODS: Subjects were 10 healthy male college students (height 174.80 ± 4.10 cm, weight 69.20 ± 8.82 kg ). The interventions, included open-stance cycling with limited ankle movement and traditional-stance cycling. Before testing, all subjects performed stretching of 5 muscle groups, including quadriceps, hamstrings, calf muscles, hip flexors, glutaeusmaximus. The warm-up was cycling for 5 minutes on a stationay ergometer (Monark, ergomedic 828E). The two tests were done on the same stationaty ergometer at 1.5 kp/70 rpm for 10 minutes. The order of the two interventions were randomly decided, and there was a two-day-interval between each. EMG data was collected by Biopac systems, MP150. Amplified surface electrodes were placed on VMO and VL of the right leg. RESULTS: There was significant difference between VMO and VL ratio for the openstance and traditional-stance cycling (p = 0.047). CONCLUSION: The results of current study demonstrated that the open-stance cycling could not change the VMO and VL ratio effectively from the traditionalstance cycling. Further studies were needed to identify the effect of lower extremity positioning on VMO/VL ratio.