In this work, 23 black soil profiles were surveyed and 113 soil samples were collected to determine the field capacity (FC) of the black soil in Northeast China. The effectiveness of three methods measuring FC, the Wi...In this work, 23 black soil profiles were surveyed and 113 soil samples were collected to determine the field capacity (FC) of the black soil in Northeast China. The effectiveness of three methods measuring FC, the Wilcox method (WM), the undisturbed soil pressure plate method (PUM) and the air-dried sieved soil pressure plate method (PDM) were compared to select a suitable laboratory measurement method. Results show that the FC values measured by PDM are greater than those measured by PUM, and the values measured by PUM are greater than those measured by WM. PUM is more suitable for the determination of FC in the study area. One regression equation between PUM and PDM has been established through which undisturbed soil can be replaced by air-dried sieved soil, which is easier to get, to measure FC. FCs vary from 23.50% to 37.00%, with an average of 31.65%, which differ greatly among the 23 black soil profiles. FC is found to be significantly positively correlated with the silt content, clay content and bulk density of the soil, but significantly negatively correlated with the sand content. An empirical pedotransfer function is established to estimate the FC using available soil physical and chemical properties.展开更多
Purpose: The purpose of the present controlled cross-sectional study was to investigate proximal femur and whole-body bone mineral density(BMD), as well as bone turnover profile, in lifelong trained elderly male footb...Purpose: The purpose of the present controlled cross-sectional study was to investigate proximal femur and whole-body bone mineral density(BMD), as well as bone turnover profile, in lifelong trained elderly male football players and young elite football players compared with untrained age-matched men.Methods: One hundred and forty healthy, non-smoking men participated in the study, including lifelong trained football players(FTE, n = 35)aged 65—80 years, elite football players(FTY, n = 35) aged 18—30 years, as well as untrained age-matched elderly(UE, n = 35) and young(UY,n = 35) men. All participants underwent a regional dual-energy X-ray Absorptiometry(DXA) scan of the proximal femur and a whole-body DXA scan to determine BMD. From a resting blood sample, the bone turnover markers(BTMs) osteocalcin, carboxy-terminal type-1 collagen crosslinks(CTX-1), procollagen type-1 amino-terminal propeptide(P1NP), and sclerostin were measured.Results: FTE had 7.3%—12.9% higher(p < 0.05) BMD of the femoral neck, wards, shaft, and total proximal femur in both legs compared to UE,and 9.3%—9.7% higher(p < 0.05) BMD in femoral trochanter in both legs compared to UY. FTY had 24.3%—37.4% higher(p < 0.001) BMD in all femoral regions and total proximal femur in both legs compared to UY. The whole-body DXA scan confirmed these results, with FTE showing similar whole-body BMD and 7.9% higher(p < 0.05) leg BMD compared to UY, and with FTY having 9.6% higher(p < 0.001) wholebody BMD and 18.2% higher(p < 0.001) leg BMD compared to UY. The plasma concentration of osteocalcin, CTX-1, and P1NP were 29%,53%, and 52% higher(p < 0.01), respectively, in FTY compared to UY.Conclusion: BMD of the proximal femur and whole-body BMD are markedly higher in lifelong trained male football players aged 65—80 years and young elite football players aged 18—30 years compared to age-matched untrained men. Elderly football players even show higher BMD in femoral trochanter and leg BMD than untrained young despite an age difference of 47 years.展开更多
Purpose: The aims of this study were to(1) investigate the health-related physical fitness profile of untrained adolescent boys in comparison to adolescent soccer players,(2) determine the intensity and enjoyment of 6...Purpose: The aims of this study were to(1) investigate the health-related physical fitness profile of untrained adolescent boys in comparison to adolescent soccer players,(2) determine the intensity and enjoyment of 6 v 6 and 4 v 4 small-sided games, and(3) evaluate the health-related effects of a short-period of soccer training in the untrained group.Methods: Forty-one adolescent boys(untrained, n = 24: age = 15.9 ± 0.6 years; trained, n = 17: age = 15.7 ± 0.7 years) were recruited. For Purpose 1,the players(n = 17) and the untrained(n = 24) boys were tested for speed, jumping power, postural balance, flexibility, and aerobic capacity. After baseline testing, Purposes 2 and 3 were addressed by randomly assigning the untrained boys to either a soccer-training group(small-sided games,2 sessions per week for 8 weeks) or to a control group, followed by identical retesting.Results: At baseline, physical fitness was higher(p < 0.001) in trained players than in untrained for aerobic fitness, sprinting, jumping power, and postural balance. Small-sided games using 6 v 6 or 4 v 4 elicited similar heart rate(HR)(mean: ~ 85% peak heart rate, HR_(peak)), rate of perceived exertion, and enjoyment responses. Over 8 weeks, the between-group analysis revealed that soccer training had a large beneficial effect on postural balance(45%) when compared with control group with unclear effects on other fitness parameters.Conclusion: Adolescent soccer players had markedly higher physical fitness compared with untrained adolescents. Small-sided soccer games practiced by untrained adolescents elicited high exercise intensity. While 8 weeks of twice-weekly soccer training sessions induced significant improvement in postural balance, the short duration of the study was not sufficient to result in between-group differences in sprint and jump performance or aerobic fitness.展开更多
Purpose： The aim of this study was to assess the effects of combining the FIFA 11＋ and acute vibration training on reactive strength index （RSI） and 505 agility. Methods： Seventy-four male collegiate soccer playe...Purpose： The aim of this study was to assess the effects of combining the FIFA 11＋ and acute vibration training on reactive strength index （RSI） and 505 agility. Methods： Seventy-four male collegiate soccer players took part in the study and were randomly assigned to FIFA 11＋ with acute vibration group （FIFA ＋ WBV）, FIFA 11＋ with isometric squat group （FIFA ＋ IS） or a control group consisting of the F1FA 11＋ alone （Con）. The warm-up consisted of the FIFA 11＋ and was administered to all participants. The participants in the acute vibration group were exposed to 30 s whole body vibration in squat position immediately post warm-up. The isometric group completed an isometric squat for 30 s immediately post warm-up. Results： RSI significantly improved pre- to post-intervention amongst FIFA ＋ WBV （p 〈 0.001） due to a decrease in contact time （p 〈 0.001） in comparison to FIFA ＋ IS and Con, but 505 agility was not affected. Conclusion： The results of this study suggest the inclusion of an acute bout of WBV post FIFA 11＋ warm-up produces a neuromuscular response leading to an improvement in RSI. Future research is required to examine the exact mechanisms behind these improvements amongst other populations and over time course of the performance.展开更多
基金Under the auspices of National Natural Science Foundation of China(No.40671111)Major State Basic Research Development Program of China(No.2007CB407203)
文摘In this work, 23 black soil profiles were surveyed and 113 soil samples were collected to determine the field capacity (FC) of the black soil in Northeast China. The effectiveness of three methods measuring FC, the Wilcox method (WM), the undisturbed soil pressure plate method (PUM) and the air-dried sieved soil pressure plate method (PDM) were compared to select a suitable laboratory measurement method. Results show that the FC values measured by PDM are greater than those measured by PUM, and the values measured by PUM are greater than those measured by WM. PUM is more suitable for the determination of FC in the study area. One regression equation between PUM and PDM has been established through which undisturbed soil can be replaced by air-dried sieved soil, which is easier to get, to measure FC. FCs vary from 23.50% to 37.00%, with an average of 31.65%, which differ greatly among the 23 black soil profiles. FC is found to be significantly positively correlated with the silt content, clay content and bulk density of the soil, but significantly negatively correlated with the sand content. An empirical pedotransfer function is established to estimate the FC using available soil physical and chemical properties.
文摘Purpose: The purpose of the present controlled cross-sectional study was to investigate proximal femur and whole-body bone mineral density(BMD), as well as bone turnover profile, in lifelong trained elderly male football players and young elite football players compared with untrained age-matched men.Methods: One hundred and forty healthy, non-smoking men participated in the study, including lifelong trained football players(FTE, n = 35)aged 65—80 years, elite football players(FTY, n = 35) aged 18—30 years, as well as untrained age-matched elderly(UE, n = 35) and young(UY,n = 35) men. All participants underwent a regional dual-energy X-ray Absorptiometry(DXA) scan of the proximal femur and a whole-body DXA scan to determine BMD. From a resting blood sample, the bone turnover markers(BTMs) osteocalcin, carboxy-terminal type-1 collagen crosslinks(CTX-1), procollagen type-1 amino-terminal propeptide(P1NP), and sclerostin were measured.Results: FTE had 7.3%—12.9% higher(p < 0.05) BMD of the femoral neck, wards, shaft, and total proximal femur in both legs compared to UE,and 9.3%—9.7% higher(p < 0.05) BMD in femoral trochanter in both legs compared to UY. FTY had 24.3%—37.4% higher(p < 0.001) BMD in all femoral regions and total proximal femur in both legs compared to UY. The whole-body DXA scan confirmed these results, with FTE showing similar whole-body BMD and 7.9% higher(p < 0.05) leg BMD compared to UY, and with FTY having 9.6% higher(p < 0.001) wholebody BMD and 18.2% higher(p < 0.001) leg BMD compared to UY. The plasma concentration of osteocalcin, CTX-1, and P1NP were 29%,53%, and 52% higher(p < 0.01), respectively, in FTY compared to UY.Conclusion: BMD of the proximal femur and whole-body BMD are markedly higher in lifelong trained male football players aged 65—80 years and young elite football players aged 18—30 years compared to age-matched untrained men. Elderly football players even show higher BMD in femoral trochanter and leg BMD than untrained young despite an age difference of 47 years.
文摘Purpose: The aims of this study were to(1) investigate the health-related physical fitness profile of untrained adolescent boys in comparison to adolescent soccer players,(2) determine the intensity and enjoyment of 6 v 6 and 4 v 4 small-sided games, and(3) evaluate the health-related effects of a short-period of soccer training in the untrained group.Methods: Forty-one adolescent boys(untrained, n = 24: age = 15.9 ± 0.6 years; trained, n = 17: age = 15.7 ± 0.7 years) were recruited. For Purpose 1,the players(n = 17) and the untrained(n = 24) boys were tested for speed, jumping power, postural balance, flexibility, and aerobic capacity. After baseline testing, Purposes 2 and 3 were addressed by randomly assigning the untrained boys to either a soccer-training group(small-sided games,2 sessions per week for 8 weeks) or to a control group, followed by identical retesting.Results: At baseline, physical fitness was higher(p < 0.001) in trained players than in untrained for aerobic fitness, sprinting, jumping power, and postural balance. Small-sided games using 6 v 6 or 4 v 4 elicited similar heart rate(HR)(mean: ~ 85% peak heart rate, HR_(peak)), rate of perceived exertion, and enjoyment responses. Over 8 weeks, the between-group analysis revealed that soccer training had a large beneficial effect on postural balance(45%) when compared with control group with unclear effects on other fitness parameters.Conclusion: Adolescent soccer players had markedly higher physical fitness compared with untrained adolescents. Small-sided soccer games practiced by untrained adolescents elicited high exercise intensity. While 8 weeks of twice-weekly soccer training sessions induced significant improvement in postural balance, the short duration of the study was not sufficient to result in between-group differences in sprint and jump performance or aerobic fitness.
文摘Purpose： The aim of this study was to assess the effects of combining the FIFA 11＋ and acute vibration training on reactive strength index （RSI） and 505 agility. Methods： Seventy-four male collegiate soccer players took part in the study and were randomly assigned to FIFA 11＋ with acute vibration group （FIFA ＋ WBV）, FIFA 11＋ with isometric squat group （FIFA ＋ IS） or a control group consisting of the F1FA 11＋ alone （Con）. The warm-up consisted of the FIFA 11＋ and was administered to all participants. The participants in the acute vibration group were exposed to 30 s whole body vibration in squat position immediately post warm-up. The isometric group completed an isometric squat for 30 s immediately post warm-up. Results： RSI significantly improved pre- to post-intervention amongst FIFA ＋ WBV （p 〈 0.001） due to a decrease in contact time （p 〈 0.001） in comparison to FIFA ＋ IS and Con, but 505 agility was not affected. Conclusion： The results of this study suggest the inclusion of an acute bout of WBV post FIFA 11＋ warm-up produces a neuromuscular response leading to an improvement in RSI. Future research is required to examine the exact mechanisms behind these improvements amongst other populations and over time course of the performance.
