ABSTRACT Introduction: This is a study on the reasonable organization and collocation of sports health elements in different sports forms, and how this is reflected through scientific exercise instructors. Objective: To improve the effect of sports medicine on the biomechanical energy metabolism of human health. Methods: The biomechanical model of knee joint stress was used to analyze the mechanical behavior of knee joint flexion, such as movement and contact; the variation law and peak value of stress on the contact surface of the tibiofemoral joint were obtained. Results: Based on the changes of stress on tibiofemoral joint contact surface and the peak value of the data obtained in this paper, the model and data basis were provided for guiding scientific sports training and sports medicine treatment, preventing knee joint sports injury, knee joint inflammation, and reasonably improving sports performance. Conclusions: Sports medicine is effective in improving human health. The objects of clinical exercise guidance include all people, from infancy to the old age. The function of exercise is recognized in the effect of the whole process of prevention, treatment and rehabilitation of a variety of clinical diseases. The effectiveness of exercise in the whole process of disease is also recognized. Level of evidence II; Therapeutic studies - investigation of treatment results.

OBJECTIVE:To study whether the two methods of energy calculation affects the value of relative energy contribution in men's T54 wheelchair racing events. METHODS:Ten men's T54 wheelchair racers (age (22.9±5.2) yrs、sitting height (90.9±3.2) cm、body mass (59.3±8.3) kg) participate in 1 incremental test and 4 time trials (400 m、800 m、1 500 m、5 000 m). A portable gas analyzer, polar heart rate belt and a blood lactate analyzer were used to measure VO2 at every breath, HR and blood lactate changes. The energetic contribution was measured with phosphocreatine-lactate-oxygen(PCr-La-O2) and maximal accumulated oxygen deficit(MAOD) methods. RESULTS:The anaerobic and total energy portions from MAOD were lower than those from PCr-La-O2 ( especially in 400 m: WTOT (50.8 ±12.7) KJ vs (65.2±13.5) KJ、WANA (31.0±9.0) KJ vs (45.4±11.4) KJ, P＜0.05), resulting in WAER% calculated by MAOD was generally higher than PCr-La-O2 method (especially in 400 m : WAER% 39.0% ±1.2% vs 30.4%±8.4 %,P＜0.05). CONCLUSION:The study proves that the two-calculation method causes WAER% difference. MAOD method does lead to an overestimate of WAER%. Recommend to use the same calculation method for diagnosis and monitoring in the longitudinal study of long-term scientific research (such as the 4-year Olympic Games),to avoiding the difference in results caused by different calculation methods, which will further influence the development of coaches' training plans and training implementation effect.

Short-distance running with change of direction (SR-COD) is one of the baseline practice regulary performed in tennis training, but the energy contributions of this practice is relatively lacking. PURPOSE: To investigate the energy contributions of tennis SR-COD, with the emphasis on the duration, distance, and frequency. METHODS: 16 collegiate male tennis players (22.2 ± 1.7yrs, 175 ± 5cm, 69.2 ± 6.1kg) volunteered to this study. Two duration (1 and 2min), two distance (1 and 2min) and two frequency (20 and 30 stroke/min) were utilized, i.e. 1min-2m-20stroke/min, 2min-2m-20stroke/min, 1min-4m-20stroke/min and 1min-2m-30stroke/min. A portable spirometric system (K4b2, Cosmed, Italy) was utilized to measure the ventilatory activities. Capillary blood from earlobe was collected and analyzed with blood lactate analyzer (Biosen C-line, EKF, Germany) prior to and post the test. The aerobic (Aer), anaerobic lactic (Anl), anaerobic alactic (Anal) energy contributions were calculated with the method based on the accumulated oxygen uptake and blood lactate during the practice, as well as the fast part of the oxygen uptake kinetics during the recovery, respectively. The relative energy contributions from the coresponding three pathways were also calculted as Aer%, Anl%, and Anal%. RESULT: The energy contributions of SR-COD was Anal 37.4~40.1kJ (32.1~41.7%), Anl 15.1~33.5kJ (14.8~30.4%) and Aer 37.8~100.8kJ (33.9~61.9%), respectively. With the increase of duration, distance and frequency, there was no significant change in Anl, there was significant increase in Anal and Aer (P<0.05, except Aer when increasing frequency). Further, %Anal decreased with the increase of duration, distance, and frequency (P<0.05). %Anl enhanced significantly with the increased distance and frequency (P<0.05), but declined insignificantly with increased duration (P<0.05). %Aer increased significantly with longer duration (P<0.05), but reduced with longer distance and higher frequency (P<0.05). CONCLUSION: Longer duration of SR-COD mainly increases the stimulation on Aers system, while longer distance and higher frequency of SR-COD mainly increases the stimulation on Anl energy. These findings should be taken into account when designing the SR-COD training program in tennis.

Objective Badminton four-corner running practice with change of direction commonly includes fix route and random route. However, the study of the energy contributions characteristics of these two training methods was very limited. The aim of this study was to investigate the influence of different route randomness on energy contributions of college students' badminton running practice with change of direction at two frequencies. Methods 15 college badminton player whom from Shanghai University of Sport (Male, N=15, 22.9±1.4 yrs, 175.7±6.0 cm, 68.0±6.4kg, badminton training experience 2.2±0.5 yrs) volunteered to perform one test for maximal oxygen uptake （VO2max） on treadmill and four field tests with two route randomness (fix route and random route, F and R ) and two frequencies (24 times per 1min and 24 times per 1min, H and L ) of change of direction. A portable spirometric system (K4b2, Cosmed, Italy) was utilized to measure the ventilator information during the test, and capillary blood was taken from earlobe and analyzed prior and post the tests. The energy contributions was calculated with the method based on the fast component of oxygen debt (WAla) , accumulated blood lactate (WLa) and VO2 (WAer)during the tests. Results Higher frequency significantly increased the energy contributions from the three pathways both with F and R (WAla:26.2±6.3 kJ vs. 39.5±12.6 kJ, WLa: 5.7±2.4kJ vs. 23.1±9.3 kJ, WAer: 27.1±6.5kJ vs. 33.3±5.7kJ, P<0.01), and significantly increased the WLa (F: 23.9±8.1% vs. 9.6±3.4%, P<0.01; R: 30.5±6.6% vs. 11.7±5.2%, P<0.01), whereas significantly reduced the WAer% (F: 35.2±6.5% vs. 46.0±8.5%, P<0.01; R: 35.7±5.4 % vs. 50.4±10.2%, P<0.01). The R significantly reduced the WLa% both in L (44.4±8.5% vs. 38.0±8.6% , P<0.05) and H (40.9±10.5% vs. 33.8±8.6%, P<0.05), significantly increased the WLa (23.1±9.3kJ vs. 28.9±7.3kJ, P<0.05) and WLa% (23.9±8.1% vs. 30.5±1.7%) in H. Conclusions The route randomness of badminton running practice with change of direction at two frequencies has different effects on the energy contributions. The R will reduce the stimulation to the WAla and increase the stimulation to the WLa ; the H will increase the intensity of the running with change of direction as a whole, and will reducing the stimulation to the WAer and increasing the stimulation to the WLa. It is recommended that the coaches can change the stimulation of the WLa by changing the frequency of the change of direction and the randomness of the route when design the badminton four-corner running practice with change of direction.

Objective Wearable resistance training is a common method ultilzed by athletic and fitness population during running. This method is demonstrated to have multiple athletic and health benefits despite of its potential risk for running technique. Running economy is a measure for running technique, which is defined as the oxygen uptake (VO2) at a given sub-maximal speed. The purpose of this study is to evaluate the effect of wearable resistance on running economy at different running speed in male collegiate students. Methods 18 male collegiate students from Shanghai University of Sports (age: 22.4±2.4yrs, height: 177.4±7.5cm, body mass: 69.3±8.2kg, training experience: 4.6±1.6yrs, body fat: 13.3±4.7%) volunteered to perform one two four-stage incremental tests (8km/h, 10km/h, 12km/h, 14km/h) with and without a trunk resistance vest (10% of individual body mass). The duration of each stage was 5 min, and intermittent per stage was 1 min. A portable spirometric system (K4b2, Cosmed, Italy) was utilized to measure the ventilator and heart rate index during the test. The running economy was calculated as the averaged VO2 in the last minute of each stage. The capillary blood was collected from the earlobe after each stage IBM SPSS Statistics 19（SPSS Statistics 19, IBM Corporation, USA）was used to carry out a one-way repeated measurement ANOVA analysis on the physiological results at different speeds, and Paired-T test was to statistical analysis the normal and trunk vest test at the same speed. P<0.05 was set as the significant level. Results Along with the increase of speed, VO2, heart rate, blood lactate concentration and RPE was increased significantly (P<0.05, except 12km/h and 14km/h without vest, and 8km/h and 10km/h with vest). The running economy was slightly lower in running with vest at each running speed compared with without vest (P>0.05). However, the blood lactic concentration with vest was higher than that without vest at all speed, with the difference significant at 14km/h(9.3±2.9 vs. 7.6±2.2mM, P>0.05). The RPE was significant higher with vest than without vest at each speed (P<0.05, except at 8km/h). Conclusions Running with trunk resistance vest of 10% body mass is characterized with slightly better economy, although it induces a significant higher blood lactic concentration and RPE.

The Hit & Turn Tennis Test (H&TTT) is an acoustically controlled on-court test designed for evaluating tennis-specific endurance. Performance levels achieved during this test has been proposed to estimate the peak oxygen uptake (VO2peak), but the validity of the regression equations warrant further investigation. PURPOSE: To evaluate the validity of H&TTT in estimating VO2peak. METHODS: Sixteen collegiate tennis players (age: 22.2 ± 1.7 yrs; height: 175 ± 5 cm; mass: 69.2 ± 6.1 kg; tennis training experience: 2.3 ± 0.8 yrs) volunteered to perform H&TTT on an indoor synthetic field. A portable spirometric system (K4b2, Cosmed, Italy) was utilized to measure the ventilatory activities to calculate VO2peak during the test. VO2peak was also estimated with a H&TTT regression equation (VO2peak=[Level*2+30]ml/min/kg).. Additionally, for the directly measured ventilator activities, two smoothing methods (5 vs. 3 successive points) were utilized to process VO2 data, and five different methods (the highest consecutive 5 points vs 5s vs 10s vs 15s) were utilized to calculate VO2peak RESULT: The levels subjects achieved in H&TTT were 14.6 ± 3.4. The estimated VO2peak were 59.3 ± 6.7ml/min/kg using the regression equation. The calculated VO2peak using different smoothing methods and criterion ranged between 53.5 ± 5.1 and 57.7 ± 6.0 ml/min/kg. No significant correlation was found between estimated and calculated VO2peak (r < 0.3, p > 0.05). Significant differences were found for calcualted VO2peak using different smoothing methods and criterion (p<0.01). CONCLUSION: Inconsistent with the literature, the validity of H&TTT in estimating VO2peak was not supported by this study. Caution should be paid when this test is utilized. In addition, a fixed method of data processing is recommended when calculating VO2 from direct measurements.

Objective Energy expenditure is an indicator that comprehensively reflects the amount of physical activity. Fitness wristbands are used to monitor the energy expenditure of human activities in the fitness field. Among the fitness wristbands popular in China, Honor and Lifesense rank in the top list. However, there was no research on the reliability and validity of these two wristbands in measuring the energy expenditure. This study aims to evalute the reliability and validity of the two fitness wristbands (Honor and Lifesense) in measuring the energy expenditure in inline and shuttle running. Methods 18 male collegiate students (age: 22.4±2.5yrs, height: 177±7cm, mass: 69.3.±8.4kg) volunteered to participate in two four-stage incremental inline running tests (8km/h, 10km/h, 12km/h, 14km/h) and two 20m four-stage incremental shuttle running test (6km/h, 8km/h, 10km/h, 12km/h). The duration of each stage was 5 min, and intermittent per stage was 1 min. Honor B3（GMN-BX9, Honor, China） and Lifesense Mombo2（LS417-B, Lifesense, China）fitness wristbands was utilized to measure the energy expenditure of each stage in incremental inline and shuttle running. A portable spirometric system (K4b2, Cosmed, Italy) was utilized to measure the ventilator information during the test. The energy expenditure was converted into equivalent units (kcal) according to the measured respiratory quotient coefficient. The repeat measuremented reliability test was carried out on the energy expenditure indicators measured by the fitness wristbands in the twice incremental inline running and the shuttle running. The energy expenditure calculated by the portable gas metabolic instrument was comparedwith those measured by Honor and Lifesense fitness wristbands. Results The result test-retest reliability found that the Honor and Lifesense fitness wristbands had well correlations between the two tests at a speed of 8km/h, 10km/h, 12km/h in inline running, and 8km/h, and 10km/h in shuttle running (r=0.44~0.93, P<0.05), but the correlation was not well at 6km/h in shuttle running (r<0.43, P>0.05). The Honor wristband correlation (r=0.83~0.93, P<0.05) was higher than the Lifesense fitness wristbands (r=0.44~0.60, P<0.05) at 8km/h, 10km/h, and 12km/h in inline running and at 8km/h, and 10km/h in shuttle running. The correlation coefficients of the two fitness wristbands at 8km/h and 10km/h in inline running (r=0.52~0.93, P<0.05) were both higher than those in shuttle running (r=0.44~0.83, P<0.05). The energy expenditure measured by K4b2 and the two kinds fitnees wristband was significantly different (P<0.05), except at 12km/h in inline running and 10km/h in shuttle running (P > 0.05). Conclusions Honor and Lifesense wristbands have acceptable reliability in measuring energy expenditure at 8, 10, 12km/h in inline and shuttle running, with the fore slightly higher than the after. The two wristbands have higher reliability in measuring the energy expenditure in inline running than in shuttle running. The validity of measuring the energy expenditure with the two fitness wristbands is acceptable at 12km/h in inline running and at 10km/h in shuttle running, but not at other speed.