Comparison of strength values and laterality in various muscle contractions between competitive swimmers and untrained persons

Competitive swimmers may gain a specific training effect as the result of long term exercise in the water. This study aimed to compare isometric, non-isokinetic and isokinetic muscle strengths in competitive swimmers and untrained persons. Twelve young male adults without exercise experience for over three years and twelve swimmers with over 10 years of competitive swimming experience performed various strength tests. Non-isokinetic tests were evaluated using one repetition of maximum half squat, vertical jump, and drop jump. Isometric and isokinetic (60 and 180 deg/s) muscle strengths were measured by both legs in knee extension and flexion. There were no significant differences between non-isokinetic and isometric muscle strengths of both groups. On the other hand, all isokinetic parameters in both angular velocities were significantly larger in competitive swimmers. There was significant laterality of isokinetic strength in untrained persons, but not in competitive swimmers. In addition, right and left differences of isokinetic strength tended to be smaller in competitive swimmers. In conclusion, competitive swimmers tended to be superior only in isokinetic strength, which is a similar muscle contraction in the water, and have less right and left differences.

Comparison of stepping parameters and center of foot pressure properties during different tempo stepping movements

This study was designed to examine the trial-to-trial reliability of stepping parameters and to compare the center of foot pressure (COP) when adapting to different tempos. Twenty healthy men (M age = 20.8, SD = 1.9 years) performed stepping tests to fixed tempos. The intra-class correlation coefficients of stepping and COP parameters were high (0.75 - 0.97). The time difference between foot contact time and fixed tempo and COP sway velocities of the X- and Y-axis were the largest at 40 beats per minute (bpm). At 60 and 120 bpm tempos, single support and swing times reflecting the stepping strategy correlated significantly with the root mean square and the velocity of the X-axis (r = I0.45 - 0.53I) . Because these step tempos are controlled largely by the automation of stepping, the single support and swing phases appeared to have a constant frequency. On the other hand, a stepping tempo of 40 bpm showed the largest sway velocity of X and Y and the smallest surrounding area mean path length. The above suggests that stepping at 40 bpm induced a larger sway area in relation to total path length and faster COP sway. Hence, it is inferred that the stepping task becomes more difficult at 40 bpm than at 60 and 120 bpm.

Gender Differences in Coffee Consumption and Its Effects in Young People

This study aimed to examine gender differences in coffee consumption and awareness of its effects in young people. To examine the above problem, a survey was conducted in 1189 young people (567 males aged 19.3 ± 1.5 years;622 females aged 19.1 ± 1.2 years). The coffee consumption rate was significantly higher in males (50.8%) than in females (32.8%). In the coffee consumption group, no significant differences were found in the reasons for consumption, the components of coffee, and its effects on health. In the coffee nonconsumption group, significant gender differences were noted in the reasons for avoiding coffee;females (64.8%) disliked its taste more than males (39.4%). More young people of both genders in the consumption group were aware that coffee contains caffeine (79.9% - 86.5%) as compared with the nonconsumption group (67.0% - 74.2%). However, few people in both groups were aware about the components other than caffeine. In addition, more people in the nonconsumption group were unaware of the adverse effects of coffee on the body. The results of this study demonstrated that young males drink coffee more than young females. Among those who avoided coffee consumption, females disliked its taste more than males. Many people regardless of coffee consumption were aware about the components of coffee, but few knew about the other ingredients in this beverage. In addition, few people were aware of the negative effects of coffee on the health and body.

Evaluating the effects of open/closed eyes and age-related differences on center of foot pressure sway during stepping at a set tempo

This study aimed to examine the effects of open/ closed eyes and age difference on Center of Foot Pressure (COP) sway during stepping. The subjects were 87 healthy males aged 10 - 80 years. COP was measured 20 times when subjects stepped on two force plates (left and right) at a rate of 60 steps/min. The evaluation parameters selected were: total trace length, velocity, circumference, rectangular area,left-right width, and front-back width. The former four of these parameters were found to be significantly lower with eyes open than eyes closed in 80-year-old subjects, while the last parameter was significantly lower with eyes open in 10-year-old subjects. In 70- and 80-year-old subjects with eyes open, circumference was greater than that in 10- and 40 - 60-year-old subjects;their rectangular area was greater than that in 50- and 60-year-old subjects;and, their front-back width was greater than that in 10- and 30 - 60-year-old subjects. With eyes closed, circumference, rectangular area, left-right width, and front-back width in 80-year- old subjects, were greater than those in 10 - 70- year-old subjects. The front-back width during stepping with eyes closed was greater in 70- and 80-year-old subjects than in 30 - 50-year-old subjects. The Romberg quotient for all COP sway parameters revealed no significant age-related differences. From our findings, a difference in body sway was observed in 80-year-old subjects (with eyes open/closed) when compared with the other age groups. In addition, the extent of sway varied little among 80 year-old- subjects have greater body sway during stepping, particularly with eyes closed.

Age and Gender Differences in the Step Test with Stipulated Tempos

This study examined differences in tempos of a step test with a stipulated tempo by age levels and gender. Subjects were 316 healthy males and females in the age range of 10 - 80 years. They performed the step test twice for 20 seconds, stepping alternately while a beeping metronome was adjusted to 40 bpm, 60 bpm, and 120 bpm. It was assumed that if the total time discrepancy between the tempos when the foot was grounded was small, people could adjust their steps to different tempos well. The results of a three-way ANOVA showed a significant age difference at 40 bpm. A multiple comparison showed that the total time discrepancy was smaller in 10 - 50 years old than in 60 - 80 years old in males and females. The total time discrepancy at 40 bpm was larger than that at 120 bpm in 10 - 50 years old, and larger in the order of 40, 60, and 120 bpm in 60 - 80 years old. The total time discrepancy showed insignificant gender differences at all ages and tempos. In conclusion, people over 60 years were less able to adjust their steps to a slow tempo than people younger than 50 years. Further, it was more difficult for people under 60 years to adjust their steps to a slower tempo, and a difference in tempos in people over 70 years largely affected their step movements.