Relationships between running performance and the cross–sectional area of the psoas major, and peak oxygen uptake in elite junior long–distance runners / 体力科学

The purpose of this study was to examine the relationships between running performance and the cross–sectional area of the psoas major, peak oxygen uptake, and running economy in male junior long–distance runners. The subjects were 37 male junior athletes who achieved good records in interscholastic athletic competition during 5 years (2011–2015). Their seasonal best times in a 5,000 m race (5,000m–SB) were 14:04.11 ± 0:07.25 (13:53.64–14:16.15). In a multiple regression analysis, 5,000m–SB was statistical significantly correlated with the cross–sectional area of psoas major (16.0 ± 1.7 cm²) measured on magnetic resonance imaging and peak oxygen uptake (4.25 ± 0.36 l min^-1 [76.9 ± 5.8 ml min^-1 kg^-1]) during a lactate curve test comprising five stages. However, 5,000m–SB was not related to oxygen uptake at the work–load which was less than the load at the lactate threshold estimated by using the lactate curve test results. These results suggest that a high volume of the psoas major, the largest hip–flexor muscle, and peak oxygen uptake are among the important factors for junior long–distance runner performance.

Nutrition interventions improve anemic status in male college long-distance runners / 体力科学

College athletes often tend to suffer from defective nutrition status due to excessive physical training with inadequate dietary intakes, which resulted in various physical disorders such as anemia. This study was conducted to investigate the effects of nutrition interventions to the anemic state of long distance runners. A nutritional education program was applied and daily single pack of nutritional supplement drink rich in iron, zinc, copper, selenium as well as eleven vitamins were provided for two months. Blood hemoglobin, red blood cells as well as serum ferritin and iron levels after the intervention were significantly higher compared with the basal, pre-intervention level of respective items. Among the subjects, two were found to be anemic (hemoglobin<13g/dl) before the intervention. Both of them, however, were successfully recovered to normal status (hemoglobin≧13g/dl) thereafter. The pre-intervention levels of hemoglobin were negatively correlated to the amount of difference between those of pre- and post-intervention, which appeared to indicate an improvement of nutrient deficiency that caused the hypochromia. On the other hands, the intake of energy and nutrients from meals did not change before and after the intervention. From the results obtained, it seems to be appropriate to emphasize the importance of nutrition education, especially, a possible effectiveness of including multiple nutrient supplementation in nutrition program for college athletes is suggested.

INFLUENCE OF DIFFERENT STRETCHING ON RANGE OF MOTION AND RUNNING ECONOMY IN LONG DISTANCE RUNNERS / 体力科学

The purpose of this study was to examine the influence of autostretching and static stretching on range of motion (ROM) and running economy (RE) in long-distance runners. Twenty-two male distance runners were randomly assigned to an autostretching group (n=8), a static stretching group (n=7) and non-intervention control group (n=7). The experimental protocol was composed of interventions between treadmill runnings for RE. The interventions were either autostretching or static stretching, after the first treadmill running. The oxygen consumption (VO₂) as RE was measured at three steady-state running speeds (240m/min, 268m/min, and 295m/min). Goniometric measurements of hip flexion and ankle dorsiflexion ROM were taken immediately before and after each treadmill running for RE. The results showed that the autostoretching group had a significant decrease in VO₂ at 240m/min (p＜0.05), and at 268m/min (p＜0.05). On the other hand, the control group had a significant increase in VO₂ only at 295m/min (p＜0.05). At the same time, the autostretching group had significant improvements in ROM for hip flexion (p＜0.05) and ankle dorsiflexion (p＜0.05). The static stretching group had no significant changes in RE or ROM. The results of this experiment suggest that autostretching had a positive effect in improving RE in subjects of this study, and indicate the possibility that improved RE leads to the improvement of long-distance runners' performance.

The Effect of Grape Procyanidins on Hemorheology in Long Distance Runner in vitro and in vivo / 中国慢性病预防与控制

Objective To study the effects of Grape Procyanidins(GPC)on hemorheology in long distance runner.Method In vitro study: 22 long distance runners were divided into two groups randomly,the experimental group and control group.With ten days period,the experimental group was given GPC 200 mg per day;while the control group were given the capsule of starch 200 mg per day.In vivo study: the vein blood samples were taken from 5 long distance runners and every example was divided into five parts,and then treated with different concentrations of GPC or H2O2.Items of the hemorheology such as Er,HCT,Eb,Ep,PFC and VAI were tested both in vivo and vitro before and after the study.Results in vitro study: all items of the experimental group showed significant decline at then end of the study than those before the study.The contents of Er,Eb and Ep before the study(6.830?0.164,4.145?0.177,1.647?0.020,respectively) were significantly higher than those after the study(6.759?0.158,4.088?0.173,1.621?0.013,respectively)(P

Zinc balance in male student long distance runners / 体力科学

To determine the zinc (Zn) status in long distance runners during the period after the running season, Zn balance was measured in 12 male student long distance runners for five days. Daily dietary intake of energy and Zn were 3000 kcal and 38 mg, respectively. Twenty-four-hour urine Zn excretion exceeded the standard value, the serum Zn concentration was within the normal range, and the sweat Zn concentration was relatively low, but prominently positive Zn balances were observed 11 of the 12 subjects. These results suggest that the Zn status in long distance runners during runnning season is low or deficient.

A STUDY OF SYSTOLIC TIME INTERVALS OF ATHLETES / 中国运动医学杂志

The purpose of this study is to investagate the meaning of systolic time intervals (STI) in evaluating cardiac functional condition of athletes.1. STI and step test were examined on 13 sprinters, 8 jumpers, 5 throwers and 5 distance runners during early, middle and the last phases in summer training season.No significant changes of the left ventricular ejection time (LVET), the pre-ejection period (PEP) and PEP/LVET ratio were found from examinations on athletes in the three different phases.The cases were divided into two groups of PEP/LVET ratio increased more than 0.05 (N=8) and PEP/LVET ratio decreased more than 0.05 (N=10) by the different of PEP/LVET ratio between linked phases examinations. Athough two of PEP/LVET ratio of each group were different evidently (P