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INTRODUCTION: This randomized, cross-over trial assessed the effect of a single bout of high-impact exercise on serum markers of bone formation and bone resorption over a 24 h period. METHODS: Twenty healthy males and females performed a single bout of brief jumping exercise (EXC) or no exercise (CON), 55 min following consumption of a standard breakfast. Blood markers of bone formation (P1NP) and bone resorption (CTX-I) were assessed before (t = 0 h) and over a 5 h period after breakfast, and following 24 h of post-exercise recovery (t = 24 h). RESULTS: Serum CTX-I concentrations decreased during the 5 h postprandial period (time-effect, P < 0.001) with no differences between conditions (time x condition, P = 0.14). After a ~ 16 % decline during the first 30 min following breakfast, serum P1NP concentrations gradually returned to baseline values during the 5 h postprandial period, with no differences in the overall response between conditions (time-effect, P < 0.001; time x condition, P = 0.25). Fasted serum CTX-I concentrations decreased from 0.33 ± 0.15 and 0.35 ± 0.15 ng/mL at baseline, to 0.31 ± 0.13 and 0.31 ± 0.16 ng/mL at t = 24 h in CON and EXC, respectively, with no differences between conditions (time-effect, P < 0.01; time x condition, P = 0.70). Fasted serum P1NP concentrations did not change from baseline to t = 24 h in both CON (baseline: 76 ± 27 ng/mL, t = 24 h: 79 ± 26 ng/mL) and EXC (baseline: 80 ± 24 ng/mL, t = 24 h: 77 ± 29 ng/mL; time-effect, P = 0.89), with no differences between conditions (time x condition, P = 0.22). CONCLUSION: High-impact exercise does not modulate the concentrations of the serum marker of bone formation P1NP and the serum marker of bone resorption CTX-I throughout a 24 h recovery period in healthy adults.

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Postmenopausal osteoporosis is a chronic condition with decreased bone mass and altered bone structure, leading to a greater risk of fractures among older women. Exercise has been proposed as a potentially effective non-pharmacological method to prevent this condition. In this systematic review, we investigate the effects and safety of high-impact and high-intensity exercises in improving bone density at popular sites of fragility fractures, namely, the hip and spine. This review also highlights the mechanism of these exercises in improving bone density and other aspects of bone health in postmenopausal women.  This study is done adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. After applying the eligibility criteria, we selected 10 articles from PubMed and Google Scholar to be included in our study.  Based on the findings from the studies, we established that high-intensity and high-impact exercises are effective in improving, or at the very least maintaining, bone density in the lumbar spine and femur in postmenopausal women. An exercise protocol including high-intensity resistance exercises and high-impact training is shown to be most effective in improving bone density and other parameters of bone health. These exercises were found to be safe in older women, however, careful supervision is recommended. All limitations considered, high-intensity and high-impact exercises are an effective strategy to enhance bone density, and potentially reduce the burden of fragility as well as compression fractures in postmenopausal women.

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INTRODUCTION: We assessed whether collagen supplementation augments the effects of high-impact exercise on bone turnover and whether a higher exercise frequency results in a greater benefit for bone metabolism. METHODS: In this randomized, cross-over trial, 14 healthy males (age 24 ± 4 y, BMI 22.0 ± 2.1 kg/m2) performed 5-min of high-impact exercise once (JUMP+PLA and JUMP+COL) or twice daily (JUMP2+COL2) during a 3-day intervention period, separated by a 10-day wash out period. One hour before every exercise bout participants ingested 20 g hydrolysed collagen (JUMP+COL and JUMP2+COL2) or a placebo control (JUMP+PLA). Blood markers of bone formation (P1NP) and resorption (CTXI) were assessed in the fasted state before the ingestion of the initial test drinks and 24, 48, and 72 h thereafter. In JUMP+PLA and JUMP+COL, additional blood samples were collected in the postprandial state at 1, 2, 3, 4, 5 and 13 h after ingestion of the test drink. RESULTS: In the postprandial state, serum P1NP concentrations decreased marginally from 99 ± 37 to 93 ± 33 ng/mL in JUMP+COL, and from 97 ± 32 to 92 ± 31 ng/mL in JUMP+PLA, with P1NP levels having returned to baseline levels after 13 h (time-effect, P = 0.053). No differences in serum P1NP concentrations were observed between JUMP+PLA and JUMP+COL (time x treatment, P = 0.58). Serum CTX-I concentrations showed a ~ 50 % decline (time, P < 0.001) in the postprandial state in JUMP+COL (0.9 ± 0.3 to 0.4 ± 0.2 ng/mL) and JUMP+PLA (0.9 ± 0.3 to 0.4 ± 0.2 ng/mL), with no differences between treatments (time x treatment, P = 0.17). Fasted serum P1NP concentrations increased ~8 % by daily jumping exercise (time-effect, P < 0.01), with no differences between treatments (time x treatment, P = 0.71). Fasted serum CTX-I concentrations did not change over time (time-effect, P = 0.41) and did not differ between treatments (time x treatment, P = 0.58). CONCLUSIONS: Five minutes of high-impact exercise performed daily stimulates bone formation during a 3-day intervention period. This was indicated by an increase in fasted serum P1NP concentrations, rather than an acute increase in post-exercise serum P1NP concentrations. Collagen supplementation or an increase in exercise frequency does not further increase serum P1NP concentrations. The bone resorption marker CTX-I was not affected by daily short-duration high-impact exercise with or without concurrent collagen supplementation.

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PURPOSE: To examine the effects of three types of school-based exercises on bone health and physical fitness function in Chinese boys and girls. METHODS: One hundred and seventy-four Chinese boys and girls were randomly assigned into four groups: (1) sham exercise (ShEx); (2) high-impact exercise (HiEx); (3) high-impact exercise with various directions (HiExVi); and (4) high-intensity interval exercise (HiInEx). Speed of sound (SOS) and physical fitness parameters were determined before and after six-month intervention. RESULTS: At the end of six-month intervention, participants in all groups show an increment of SOS compared with the baseline (p < 0.05), and the changes were higher in HiEx (mean: 38.878 m/s, 95% CI: 32.885~44.872, p = 0.001) and HiExVi groups (49.317 m/s, 42.737~55.897, p < 0.001) compared with ShEx group (20.049 m/s, 13.751~26.346). Six-month exercise training generated a reduction of percent of body fat (PBF) and waist-hip ratio (WHR) (p < 0.05). The decrease of PBF was greater in HiExVi (-1.222%, -1.820~-0.624, p = 0.012) and HiInEx groups (-1.395%, -1.809~-0.982, p = 0.003), whereas the reduction of WHR was larger in HiEx (-0.026, -0.039~-0.014, p = 0.009), HiExVi (-0.024, -0.036~-0.012, p = 0.021), and HiInEx groups (-0.035, -0.046~-0.024, p < 0.001) compared with ShEx group. Balance function (BLF), vital capacity (VC), standing long jump (SLJ), and sit up (SU) increased in all intervention groups (p < 0.05). The BLF increased in HiEx (6.332 s, 4.136~8.528, p = 0.001), HiExVi (10.489 s, 8.934~12.045, p < 0.001), and HiInEx groups (9.103 s, 7.430~10.776, p < 0.001) showed a greater change than that of ShEx group (1.727 s, 0.684~2.770). The increment of VC (273.049 mL, 199.510~346.587, p < 0.001) and SU (2.537 times/min, 0.639~4.435, p = 0.017) was higher in HiInEx group, whereas the accrual in SLJ was larger in HiExVi (7.488 cm, 4.936~10.040, p = 0.007) compared with ShEx group (58.902 mL, 7.990~109.814; -0.463 times/min, -2.003~1.077; 1.488 cm, -0.654~3.630). CONCLUSION: The brief school-based exercises were effective in improving schoolchildren's health, but they showed different effects, with HiEx mostly improving bone health, HiInEx largely benefiting physical fitness function, and HiExVi enhancing both bone and physical fitness.

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This study examined resting levels of catabolic and anabolic osteokines related to Wnt signaling and their responses to a single bout of plyometric exercise in child and adolescent females. Fourteen premenarcheal girls [10.5 (1.8) y old] and 12 postmenarcheal adolescent girls [15.0 (1.0) y old] performed a plyometric exercise trial. One resting and 3 postexercise blood samples (5 min, 1 h, and 24 h postexercise) were analyzed for sclerostin, dickkopf-1 (DKK-1), osteoprotegerin (OPG), receptor activator of nuclear factor kappa-ß ligand (RANKL), and transforming growth factors (TGF-ß1, TGF-ß2, and TGF-ß3). Premenarcheal girls had significantly higher resting sclerostin, TGF-ß1, TGF-ß2, and TGF-ß3 than the postmenarcheal girls, with no significant time effect or group-by-time interaction. DKK-1 was higher in premenarcheal compared with postmenarcheal girls. There was an overall significant DKK-1 decrease from baseline to 1 h postexercise, which remained lower than baseline 24 h postexercise in both groups. There was neither a significant group effect nor group-by-time interaction in OPG, RANKL, and their ratio. RANKL decreased 5 min postexercise compared with baseline and remained significantly lower from baseline 24 h following the exercise. No changes were observed in OPG. OPG/RANKL ratio was significantly elevated compared with resting values 1 h postexercise. In young females, high-impact exercise induces an overall osteogenic effect through a transitory suppression of catabolic osteokines up to 24 h following exercise.

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Physical activity during growth increases bone mass and strength; however, it remains unclear whether these benefits persist. The purpose of this study was to determine: (a) if bone loading during adolescence (13-18 years) or young adulthood (19-29 years) in men is associated with greater bone mineral density (BMD) in adulthood; (b) if current participation in high-impact activity (ground reaction force>4×body weight) and/or resistance training is associated with greater BMD; and, (c) if continuous participation in a high-impact activity from adolescence to adulthood is associated with greater BMD. Apparently healthy, physically active men aged 30 to 65 years (n=203) participated in this cross-sectional study. Exercise-associated bone loading was estimated based on ground reaction forces of historical physical activity. Current BMD was measured using dual-energy X-ray absorptiometry. Participants were grouped based on current participation in a high-impact activity (n=18), resistance training (n=57), both (n=14), or neither (n=114); groups were compared by two-way analysis of covariance. Bone loading during adolescence and young adulthood were significant, positive predictors of BMD of the whole body, total hip, and lumbar spine, adjusting for lean body mass and/or age in the regression models. Individuals who currently participate in a high-impact activity had greater lumbar spine BMD than nonparticipants. Men who continuously participated in a high-impact activity had greater hip and lumbar spine BMD than those who did not. In conclusion, physical activity-associated bone loading both during and after skeletal growth is positively associated with adult bone mass.

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