Jumping Exercise Research Articles

Breast Support Garments are Ineffective at Reducing Breast Motion During an Aqua Aerobics Jumping Exercise.

The buoyant forces of water during aquatic exercise may provide a form of ‘natural’ breast support and help to minimise breast motion and alleviate exercise induced breast pain. Six larger-breasted females performed standing vertical land and water-based jumps, whilst wearing three breast support conditions. Underwater video cameras recorded the motion of the trunk and right breast. Trunk and relative breast kinematics were calculated as well as exercised induced breast pain scores. Key results showed that the swimsuit and sports bra were able to significantly reduce the superioinferior breast range of motion by 0.04 and 0.05 m, respectively, and peak velocity by 0.23 and 0.33 m/s, respectively, during land-based jumping when compared to the bare-breasted condition, but were ineffective at reducing breast kinematics during water-based jumping. Furthermore, the magnitude of the swimsuit superioinferior breast range of motion during water-based jumping was significantly greater than land-based jumping (0.13 m and 0.06 m), yet there were no significant differences in exercise induced breast pain, thus contradicting previously published relationships between these parameters on land. Furthermore, the addition of an external breast support garment was able to reduce breast kinematics on land but not in water, suggesting the swimsuit and sports bras were ineffective and improvements in swimwear breast support garments may help to reduce excessive breast motion during aqua aerobic jumping exercises.

Effects of plyometric exercise session on markers of bone turnover in boys and young men.

The acute exercise effects on bone markers in adults are unclear, while in children, there are no such data. To investigate the acute response of biochemical markers of bone turnover to a high-impact exercise session consisting of high-mechanical loading in boys and young men. Twelve boys (10.2 ± 0.4 years) and 14 men (22.0 ± 0.8 years) underwent a protocol of plyometric jumping exercises (total 144 jumps). Venous blood samples were collected pre-, 5 min, 1 and 24 h post-exercise, and analyzed for markers of bone formation and resorption: bone-specific alkaline phosphatase (bone ALP), osteoprotegerin (OPG), amino-terminal cross-linking telopeptide (NTx), and receptor activator of nuclear factor kappa beta ligand (RANKL). Boys had higher resting bone ALP (111.9 ± 29.2 vs. 30.6 ± 11.2 µg/L, p < 0.05) and NTx levels (49.8 ± 13.2 vs. 21.7 ± 5.9 nM BCE, p < 0.05) than men but no group differences were observed in resting OPG or RANKL. Following exercise (24 h), bone ALP and NTx increased in both boys and men (bone ALP: 24.1 vs. 9.9%, respectively; NTx: 23.5 vs. -5%, respectively), although the group-by-time interaction was not statistically significant. OPG increased significantly (p < 0.05) in both groups (5.7 and 16.1 %, respectively). Even one session of plyometric exercises appear to stimulate bone formation in boys and men, as reflected by the increase in bone ALP and OPG. The boys' response appears more pronounced than the men's, suggesting that during growth, cellular bone activities respond with greater magnitude to mechanical stimuli.

Time-course Of Changes In Maximal Force And Rate Of Force Development After A Plyometric Training Session

Plyometric exercise causes reductions in muscular performance that may persist for several days. However, there may be differences in the magnitude and the duration of changes in maximal force and muscle power. PURPOSE: To evaluate the effects of a single session of plyometric training on the time-course of changes in maximal force and rate of force development (RFD) measured during maximal isometric and dynamic exercise METHODS: Seven moderately trained university students (4 males and 3 females, age: 20.0±0.7 yrs, height: 174±3 cm, body mass: 70±5 kg) performed a plyometric training session consisting of 3 sets of 10 repetitions of 7 jumping exercises: drop, scissor, box, stride crossover and depth jumps and steps and single leg hops on the track (total volume: 210 jumps), with 1 min recovery between sets and 3 min between exercises. Maximal isometric leg press strength and RFD (knee angle set at 90o) and countermovement jump (CMJ) height and RFD were measured using a force platform, before, 30 min after and 24, 48, 72, and 144 h after the plyometric training session. Data were analyzed using one-way ANOVA with repeated measures and Tukey’s post-hoc test. RESULTS: Maximal isometric force was decreased by 26±9% (from 3541±456 to 2436±256 N, p<0.05) only 30 min post-training and returned to baseline after 24 h. However, RFD during isometric exercise was decreased to a greater extent 30 min after (-38±9%, p<0.01), remained lower than baseline 24 h later (-16±8%, p<0.05) and returned to baseline 48 h after training. The reduction in CMJ height was larger 48 h after training (-7.2±2.5 %, p<0.05) and remained below baseline for 72 h after training (-5.2±2.5 %, p<0.05). RFD during the CMJ exhibited a decrease that was larger 48 h after training (-30±9 %, p<0.01) and persisted until the 72 h time-point. CONCLUSION: These data show that a single training session with a high volume of plyometric jumping exercises reduces maximal isometric force only temporarily, while the decrease in RFD is larger and persisting, especially during dynamic muscle contractions.

Changes in Muscle Strength and Performance after a Plyometric Training Session in Children and Adults

Although the effects of eccentric exercise on muscular performance have been examined in adults, there is little research on the effects of plyometric training in children. PURPOSE: To evaluate the effects of a single session of plyometric training on the time-course of changes in maximal force and rate of force development (RFD) measured during maximal isometric and dynamic exercise METHODS: Seven moderately trained university students (age: 21.0±1.1 yrs, height: 173±5 cm, body mass: 74±8 kg) and four children (age 11.0±0.5 yrs, height: 151±5 cm, body mass: 38±3 kg) performed a plyometric training session comprised of 10 repetitions of the following 7 jumping exercises: drop, scissor, box, stride crossover and depth jumps and single leg steps and hops on the track (total volume: 70 jumps), with 1 min recovery between sets and 3 min between exercises. Maximal isometric strength and RFD of the knee extensors (knee angle set at 90o) and countermovement jump (CMJ) performance were measured using a force platform, before, 30 min after and 48 and 102 h after the plyometric training session. Data were analyzed using two-way ANOVA with repeated measures and Tukey’s post-hoc test. RESULTS: Maximal isometric force before training was higher in adults compared with children (2031±194 vs. 504±58 N, p<0.001) and remained unchanged in both adults and children at all time-points. RFD during isometric exercise was also higher in adults compared with children (6266±1665 vs. 970±262 N.s-1, p<0.001) and remained unchanged in children, but was decreased in adults by 17.3±5.6% (p=0.02) and 8.6±4.2% (p=0.04) 30 min and 48 h after training, respectively. CMJ performance was similarly decreased 30 min after training in adults and children (-13.9±3.8%, p<0.01 and (-10.2±2.9%, p=0.03, respectively), but 48 later, it remained below the pre-training values only in adults (-6.8±3.1%, p=0.05) and had fully recovered in children. CONCLUSION: A single training session of low volume plyometric jumping exercises does not affect maximal isometric force in both children and adults. However, RFD and CMJ performance 48 h after training are only decreased in adults, while children exhibit a faster muscular performance recovery which may be explained by their lower absolute strength and their fewer fast-twitch muscle fibres.

Differential Sclerostin Response To A Plyometric Exercise Session In Boys And Men

Sclerostin is a protein encoded by the SOST gene; a negative regulator of bone that acts through inhibition of Wnt signaling and bone formation. Circulating sclerostin levels decrease during puberty and increase in adulthood. Another central player in bone turnover is parathyroid hormone (PTH), which stimulates bone resorption. Sclerostin has been shown to decrease following 24 hr mechanical stimulation in mature mice. Its response to exercise in humans and, especially in children, in whom high impact physical exercise benefits bone structure and mineralization, is unclear. PURPOSE: To investigate the acute response of sclerostin to an exercise session consisting of high mechanical loading in boys and men. METHODS: Twelve boys (10.2±1.3 y.o) and 14 young men (22.0±2.8 y.o) underwent a protocol of plyometric jumping exercises (total 144 jumps). Blood samples were collected pre, 5 minutes, 1 hour and 24 hours post-exercise session. Sclerostin and parathyroid hormone (PTH) were measured in the serum using commercial ELISA kits. RESULTS: Boys had significantly (p<0.05) higher resting values of sclerostin compared with men (150±37 vs. 112±34 pg/ml, respectively), but no difference in resting PTH values. Following exercise, sclerostin increased significantly in men but not in boys (at 5 min: 53±37% vs. 14±22%, respectively, p=0.002)). PTH levels were similar in boys and men throughout the 24-hour study period, increasing after 5 min and decreasing subsequently. CONCLUSION: Although the PTH response was similar in boys and men, sclerostin response was markedly different: a session of high impact exercise resulted in immediate increase in sclerostin in men but not in boys. The underlying mechanisms and implication of this differential response on bone formation and resorption need to be examined. Supported by Brock University and NIH Grant P01HD-04872

Crossbreed genetic performance study in the eventing horse competition

Eventing is an equestrian discipline combining dressage, show jumping and cross-country exercises. The Spanish Sport Horse (SSH) was used in this study as an example to develop a method to ascertain the influence of parental breeds on particular performances by linking their parental genetic contribution with the individual phenotype value computing the optimal breed contribution for each trait evaluated in eventing. Data included 1220 eventing records from 210 SSH animals. The genetic contribution of six main founder populations were computed for each SSH: the Spanish Purebreed (SPB), Arab Horse (A), Thoroughbred (TB), Selle Français (SF), German breeds (G) and North(-west) European (N) breeds. For this analysis we used BLUP (best linear unbiased predictor) animal models for five defined traits and for the total score. The genetic contribution as linear and quadratic adjustment and the interaction between genetic contributions were included as covariates in the genetic model to separate the possible combining ability from the breeding values. The optimal breed genetic contribution for each trait was maximised by using a simplex method. The best combination for conformation was 51% SPB and 49% N, for cross-country aptitude 23% SPB and 77% N, for dressage 48% SF and 52% N, and for show jumping 64% A and 36% N. For cross-country the best performance was predicted using 100% N genetic contribution and for the total score of 24% SF and 76% N. The combination of two breeds (group of breeds) seemed to be the best option for most of the traits. Although the results should be interpreted with caution, the importance of this paper is that it can be considered as a starting point of the analysis. The methodology applied here performed nicely in searching for the best contribution of several breeds to find the best combination for particular interests and could, therefore, be useful for other species/populations.

Changes in Bone Metabolism and Antioxidant Status with Combined Exercise and Honey Supplementation in Young Female Rats

Purpose: To investigate the effects of combined jumping exercise and honey supplementation on bone metabolism and antioxidant status in female rats. Methods: Forty eight 12-week old Sprague Dawley female rats were divided into four groups: control group (C), honey group (H), jumping group (J), and combined jumping and honey group (JH). Jumping exercise consisted of 40 jumps/day for 5 days/week at a height of 40 cm. Honey was given to the rats at a dosage of 1 g/kg body weight/rat/day via force feeding for 7 days/week. At the end of the study, tibial proximal volumetric total Bone Mineral Density (BMD) and volumetric trabecular BMD, serum total calcium, serum Alkaline Phosphatase (ALP) (bone formation marker), serum C-terminal telopeptide of type 1 procollagen (1CTP) (bone resorption marker), serum F 2 -isoprostanes (oxidative stress marker) and serum Total Antioxidant Status (TAS) were measured. Results: There were no significant differences in tibial proximal volumetric total BMD and volumetric trabecular BMD among all the groups. Eight weeks of jumping exercise and honey supplementation resulted in statistically significant higher serum total calcium concentration in JH group as compared to C, H and J groups (p < 0.05). Serum ALP was significantly higher in J group as compared to C group (p < 0.05). On the other hand, serum 1CTP was significantly lower in JH as compared to the other three experimental groups. The concentration of F2-isoprostanes was not statistically different among all the groups. Serum TAS was significantly higher in JH and H groups as compared to C group (p < 0.05) respectively. Conclusion: The results of the present study showed that 8 weeks of jumping exercise and honey supplementation significantly reduced bone resorption and enhanced antioxidant status, but did not seem to elevate oxidative stress marker.

Bone Mechanical Properties and Mineral Density in Response to Cessation of Jumping Exercise and Honey Supplementation in Young Female Rats.

This study investigated effects of cessation of exercise and honey supplementation on bone properties in young female rats. Eighty-four 12-week-old Sprague-Dawley female rats were divided into 7 groups: 16S, 16J, 16H, 16JH, 8J8S, 8H8S, and 8JH8S (8 = 8 weeks, 16 = 16 weeks, S = sedentary without honey supplementation, H = honey supplementation, and J = jumping exercise). Jumping exercise consisted of 40 jumps/day for 5 days/week. Honey was given to the rats at a dosage of 1 g/kg body weight/rat/day via force feeding for 7 days/week. Jumping exercise and honey supplementation were terminated for 8 weeks in 8J8S, 8H8S, and 8JH8S groups. After 8 weeks of cessation of exercise and honey supplementation, tibial energy, proximal total bone density, midshaft cortical moment of inertia, and cortical area were significantly higher in 8JH8S as compared to 16S. Continuous sixteen weeks of combined jumping and honey resulted in significant greater tibial maximum force, energy, proximal total bone density, proximal trabecular bone density, midshaft cortical bone density, cortical area, and midshaft cortical moment of inertia in 16JH as compared to 16S. These findings showed that the beneficial effects of 8 weeks of combined exercise and honey supplementation still can be observed after 8 weeks of the cessation and exercise and supplementation.

Sonic trampoline: the effect of audio feedback on the user experience during an exercise of jumping

In this paper we examine the influence of auditory augmentation on the act of jumping on an elastic trampoline. To do so we have developed a system that interactively augments the sound of a trampoline when a user is jumping on it. The sound design is inspired by iconic jumping sounds from games and the synthesis engine allows for parametric control of the sound features. The sensing technology is based on a combination of motion tracking with depth camera and audio-based contact sensing between the feet and the trampoline. The system lets the user interactively control the sound by jumping. We conducted a study to evaluate the effect of manipulating the auditory feedback during the jumping exercises. Results show that our interactive sonification positively affects the user experience during the exercise and stimulates changes in the user's behavior toward increased performance. Our system and study provide evidence that interactive sonification can act as a motivational tool in training and add an extra fun-factor to body-controlled games.

Physical activity and bone mineral density

The bones play an important structural role in the organism. They provide mobility, support, and protect the body, and the place where the storage essential minerals. Healthy bones have a crucial impact on the overall health of a person, and activities that promote health and preventive influence on the formation of bone disease are crucial in maintaining a strong and healthy skeletal system. Physical inactivity affects the decrease in function of bone, and the most common disease of bone osteoporosis. Osteoporosis is a systemic skeletal disorder that results in low bone density and micro-architectural deterioration of bone tissue, that results in less bone density, and may lead to fracture. Physical activity is essential for bone health and prevention of osteoporosis. Based on available information, the best effect to maintain and stimulate the formation of bone mineral density is a combination of dynamic exercises with resistance training that engage multiple joints, large muscle groups, and have influence on the spine and hips. The results suggest that exercises with axial loading, such as running, jumping, and power exercise, promote the positive gains in bone mineral density. Therefore, training should focus on the adaptation of specific parts of the body that is most susceptible to injury, and should be sufficiently intense that exceeds the normal loads.

Efficiency of jumping exercise in improving bone mineral density among premenopausal women: a meta-analysis.

Jumping exercise is frequently regarded as an optimum strategy for increasing pubertal bone growth, but its role in promoting or preserving adult bone mineral density (BMD) is still undefined. This meta-analysis aimed to evaluate the evidence for the influence of jumping exercise on BMD in premenopausal women and to define the effectiveness of high-impact exercise in improving or maintaining female bone health. We searched MEDLINE, PubMed, EMBASE, SPORTDiscus, Google Scholar and BIOSIS up to 1 September 2013 for jumping exercise influence on BMD in premenopausal women. The search terms used were 'jumping', 'skipping', 'brief exercise', 'high impact', 'bone density', 'BMD', 'femoral neck', 'lumbar spine', and 'trochanter', and the search was limited to females. Six papers met the search criteria. Six studies on BMD in the femoral neck (Q = 2.63, p = 0.854, I (2) = 0.0 %), trochanter (Q = 2.10, p = 0.10, I (2) = 0.0 %) and lumbar spine (Q = 1.17, p = 0.979, I (2) = 0.0 %) were highly homogenous in determining skeletal responses to jumping exercise. Jumping exercise significantly increased BMD in the femoral neck {weighted mean difference (WMD) [fixed effect] = 0.017 g/cm(2), 95 % confidence interval (CI) 0.014-0.20, p < 0.001} and trochanter (WMD [fixed effect] = 0.021, 95 % CI 0.018-0.024, p < 0.001). However, the lumbar spine seemed to benefit less from such high-impact exercise (p = 0.181). Visual inspection of the plots implicated some degree of asymmetry, indicating a slightly positive treatment effect at the femoral neck and trochanter sites. Based on meta-analysis of existing studies, the sensitivity of skeletal response to jumping exercise in premenopausal women is significant and site-specific, with significant benefit from high-impact exercise noted, especially at the hip.

Achilles Tendon Biomechanics in Response to Acute Intense Exercise

Achilles tendinopathy is a common disorder and is more prevalent in men. Although differences in tendon mechanics between men and women have been reported, understanding of tendon mechanics in young active people is limited. Moreover, there is limited understanding of changes in tendon mechanics in response to acute exercise. Our purpose was to compare Achilles tendon mechanics in active young adult men and women at rest and after light and strenuous activity in the form of repeated jumping with an added load. Participants consisted of 17 men and 14 women (18-30 years) who were classified as being at least moderately physically active as defined by the International Physical Activity Questionnaire. Tendon force/elongation measures were obtained during an isometric plantarflexion contraction on an isokinetic dynamometer with simultaneous ultrasound imaging of the Achilles tendon approximate to the soleus myotendinous junction. Data were collected at rest, after a 10-minute treadmill walk, and after a fatigue protocol of 100 toe jumps performed in a Smith machine, with a load equaling 20% of body mass. We found greater tendon elongation, decreased stiffness, and lower Young's modulus only in women after the jumping exercise. Force and stress were not different between groups but decreased subsequent to the jumping exercise bout. In general, women had greater elongation and strain, less stiffness, and a lower Young's modulus during plantarflexor contraction. These data demonstrate differences in tendon mechanics between men and women and suggest a potential protective mechanism explaining the lower incidence of Achilles tendinopathy in women.

Increased resistance during jump exercise does not enhance cortical bone formation.

This study sought to elucidate the effects of a low- and high-load jump resistance exercise (RE) training protocol on cortical bone of the tibia and femur mid-diaphyses. Sprague-Dawley rats (male, 6 months old) were randomly assigned to high-load RE (HRE; n = 16), low-load RE (LRE; n = 15), or cage control (CC; n = 11) groups. Animals in the HRE and LRE groups performed 15 sessions of jump RE for 5 wk. Load in the HRE group was progressively increased from 80 g added to a weighted vest (50 repetitions) to 410 g (16 repetitions). The LRE rats completed the same protocol as the HRE group (same number of repetitions), with only a 30-g vest applied. Low- and high-load jump RE resulted in 6%-11% higher cortical bone mineral content and cortical bone area compared with controls, as determined by in vivo peripheral quantitative computed tomography measurements. In the femur, however, only LRE demonstrated improvements in cortical volumetric bone mineral density (+11%) and cross-sectional moment of inertia (+20%) versus the CC group. The three-point bending to failure revealed a marked increase in tibial maximum force (25%-29%), stiffness (19%-22%), and energy to maximum force (35%-55%) and a reduction in elastic modulus (-11% to 14%) in both LRE and HRE compared with controls. Dynamic histomorphometry assessed at the tibia mid-diaphysis determined that both LRE and HRE resulted in 20%-30% higher periosteal mineralizing surface versus the CC group. Mineral apposition rate and bone formation rate were significantly greater in animals in the LRE group (27%, 39%) than those in the HRE group. These data demonstrate that jump training with minimal loading is equally, and sometimes more, effective at augmenting cortical bone integrity compared with overload training in skeletally mature rats.

Influences of Polymetric Jumping Exercise on Maximal Oxygen Consumption and Hemodynamics of Skeletal Muscle

Influences of Polymetric Jumping Exercise on Maximal Oxygen Consumption and Hemodynamics of Skeletal Muscle

D-25 Free Communication/Poster - Physical Activity Correlates

High impact physical training is beneficial for bone structure and mineralization and typically results in increased levels of bone turnover markers. However, the acute effects of a single exercise session on bone markers are unclear. In adults, inconsistent results have been demonstrated following high impact exercise. In children, there is a paucity of data in this area. PURPOSE: To investigate the acute response of bone turnover markers to an exercise session consisting of high mechanical loading in boys and men. METHODS: Participants underwent a protocol of plyometric jumping exercises (total 144 jumps). Venous blood samples were collected pre, 5 minutes post-, 1 hour post- and 24 hours post-exercise session to measure bone-specific alkaline phosphatase (BAP), amino-terminal cross-linking telopeptide (NTx), osteoprotegrin (OPG) and receptor activator of nuclear factor kb ligand (RANKL). RESULTS: Boys had higher BAP levels, with an increase 24 hours post-exercise (111.9±29.2 vs. 137.6±36.3 μg/L, respectively), which was not observed in the men (31.4±11.1 vs. 33.3±10.5 μg/L, respectively). NTx levels were higher in boys, with a greater increase over time in boys than in men (boys: 48.7±13.7 vs. 58.8±16.7 nM BCE pre- and 24 hours post-exercise, respectively; men: 21.7±5.4 vs. 19.4±5.0 NM BCE pre- and 24 hours post-exercise, respectively). OPG and RANKL levels were similar in boys and men before and after exercise, with no change over 24 hours. CONCLUSIONS: These results indicate that even one session of exercise stimulates bone turnover, as reflected in the increase in both BAP and NTx values, in boys (but not men) within 24 hours.

Effects of honey supplementation combined with different jumping exercise intensities on bone mass, serum bone metabolism markers and gonadotropins in female rats

BackgroundThe effects of high and low jumping exercise intensities combined with honey on bone and gonadotrophins were investigated in eighty four 9 week-old female rats.MethodsThe experimental groups were 20 or 80 jumps per day combined with or without honey supplementation (HJ20, HJ80, J20 and J80), honey supplementation (H), sedentary without supplementation control (C), and baseline control (C0) groups.ResultsStudy results showed that HJ80 elicited greatest beneficial effects on tibial and femoral mass, serum total calcium and alkaline phosphatase concentrations. There were significantly (p < 0.05) lower levels of serum follicle stimulating hormone concentrations in H, J20, J80 compared to C, with exception of HJ20 and HJ80. Serum luteinizing hormone concentrations were significantly (p < 0.05) greater in HJ20, HJ80 and J20 compared to J80.ConclusionsIt appears that high intensity jumping exercise combined with honey supplementation resulted more discernable effects on bone. Meanwhile, honey may protect against the adverse effects induced by jumping exercise on gonadotropins in female rats.

Stress Hormone and Reproductive System in Response to Honey Supplementation Combined with Different Jumping Exercise Intensities in Female Rats

This study was performed to determine the effects of 8-week honey supplementation combined with different jumping exercise intensities on serum cortisol, progesterone, estradiol, and reproductive organs. Eighty-four 9-week-old female rats were divided into 7 groups: baseline controls (C0), sedentary group (C), 20 and 80 jumps per day (Ex20J, Ex80J), honey (H), and combined honey with 20 and 80 jumps per day (HEx20J, HEx80J) groups. Jumping exercise was performed at 5 days/week and honey was given at a dosage of 1 g/kg body weight/day for 7 days/week. The level of serum cortisol was higher in Ex20J and Ex80J compared to C. There was significantly lower value of serum cortisol in HEx20J compared to Ex80J. Serum progesterone levels were significantly lower in Ex20J and Ex80J compared to C. However, serum progesterone levels were significantly higher in HEx20J and HEx80J compared to Ex20J and Ex80J. Relative uterine weights were significantly greater in HEx20J compared to C and HEx80J, respectively. There was no significant difference in estradiol level and relative ovarian weights among all the groups. Therefore, honey elicited beneficial effects in reducing the increase of cortisol and in increasing the reduce of progesterone levels induced by different intensities jumping exercise in female rats.

Changes in Bone Turnover Markers and Bone Mass with Reducing Levels of Jumping Exercise Regimens in Female Rats

To date, little is known about the effects of a reduced level of jumping exercise regimens on bone turnover markers and mass. This study investigates the effects of different jumping exercise regimens with varying exercise loads on serum bone turnover markers and bone mass in female rats. A total of 144 female rats aged 12 weeks, were divided into 12 groups as follows: no exercise for 8 (8S) or 32 weeks (32S), or 8 weeks of standard training program (8STP) consisting of 200 jumps per week (200J/w), given at 40 jumps per day (40J/d) for 5 days per week (5d/w) (8STP24E), followed by 24 weeks of exercise at loads of either 10J/d or 20J/d or 40J/d, for either 5d/w, or 3d/w, or 1d/w. Serum osteocalcin, alkaline phosphatase, C-terminal telopeptide of type 1 collagen (1CTP) concentrations, and tibial fat free dry weight were measured. Tibial mass was significantly higher in 8STP than 8S. No changes were evident in serum markers of bone turnover parameters after 8STP. Significant increases in tibial mass were observed in rats that continued to exercise at workloads of 30J/w and above after 8STP. Serum alkaline phosphatase concentrations increase whereas serum 1CTP concentrations decrease in rats given workloads of 40J/w and above. It appears, an exercise load of 30J/w, i.e. 10J/d for 3d/w, was the minimum level of continuous exercise load that was required to maintain the 8STP-induced bone gains. In addition, significant increases in bone mass in young rats following 8STP might not always be reflected by changes in serum levels of osteocalcin, alkaline phosphatase and 1CTP.

Jump exercise during hindlimb unloading protect against the deterioration of trabecular bone microarchitecture in growing young rats

Three-dimensional femoral trabecular architecture was investigated in tail-suspended young growing rats and the effects of jump exercise during the period of tail-suspension were also examined. Eight-week-old male Wistar rats (n = 24) were randomly assigned to three body weight-matched groups: a tail suspended group (SUS, n = 8); a sedentary control group (CON, n = 8) and rats primed with jump exercise during the period of tail suspension (JUM, n = 8). The jump exercise protocol consisted of 30 jumps/day, five days/week with a 40 cm jump height. After 3 weeks of jump exercise, bone mineral density (BMD) of the entire right femur was measured using dual energy X-ray absorptiometry. Three-dimensional trabecular bone architecture at the distal femoral metaphysis was evaluated using microcomputed tomography (micro-CT). Tail suspension caused a decrease in femoral BMD (−5%, p < 0.001) and trabecular bone architectural deterioration. Deterioration in the trabecular network during hindlimb unloading was mostly attributed to the reduction of trabecular number (−32%, p < 0.001) in the distal femoral metaphysis. Jump exercise during the tail suspension period increased trabecular thickness (14%, p < 0.001) and the reduction of trabecular number was suppressed. The present data indicate that jump exercise applied during hindlimb unloading could be able to inhibit bone loss and trabecular bone architectural deterioration caused by tail suspension.

Effects of Jumping Exercise and Nutritional Management on Bone Mineral Density and Bone Turnover Markers in a Young Man

The strategy for increasing bone mineral density (BMD) has not been established in young men with low BMD. We report on a case of a young man with low BMD who was treated with exercise and nutritional management. A 29-year of old man consulted our clinic because of low BMD. He was instructed to perform maximum jumping exercise (5 times per day, 5 days per week) and intake calcium (800 mg/day), vitamin D (800 IU or 20 μg/day), and vitamin K (300 μg/day) for 6 months. The lumbar spine and femoral neck BMD increased by 2.9% and 4.7%, respectively. These results suggest the effectiveness of maximum jumping exercise and nutritional management (calcium, vitamin D, and vitamin K) on the BMD of the clinically relevant skeletal sites in young men with low BMD.