This article has Open Peer Review reports available.
Effects of honey supplementation combined with different jumping exercise intensities on bone mass, serum bone metabolism markers and gonadotropins in female rats
© Mosavat et al.; licensee BioMed Central Ltd. 2014
Received: 9 June 2013
Accepted: 11 March 2014
Published: 4 April 2014
The 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.
The 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.
Study 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.
It 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.
It is well known that mechanical loading has an effective role in increasing bone health, in which an adequate exercise program can promote bone development and protect bone against age-related bone loss . Evidences show that osteogenic effects of mechanical loading are dependent on the type, magnitude and rate of the applied load . Dynamic and high magnitude loading such as jumping exercise which elicits great ground reaction force could elicit beneficial effects on bone health in rats [3–5] and humans [6–10]. Nevertheless, strenuous exercise is believed may elicit negative effects on bone properties [11–14].
Bone is a dynamic tissue that serves both mechanical and metabolic functions. Bone metabolism markers are generally accepted as good predictors of bone mass. Markers of bone formation and resorption reflect different stages of osteoblast proliferation, differentiation and bone resorption. In this study, tibial and femoral wet weights were measured to reflect bone mass, whereas serum total calcium was measured as one of the bone metabolism markers, serum alkaline phosphatase was measured as biomarker for bone formation, and C-terminal telopeptide of type 1 collagen (1CTP) was measured as biomarker of bone resorption.
Although substantial health benefits can be obtained through physical activity, high volume of exercise training is also associated with some serious risks such as menstrual disturbance in female athletes [15–18]. It is generally known that menstrual disturbance induced by strenuous physical activity may be due to hypothalamic dysfunctions. The relationship between the brain and the ovaries is called hypothalamic-pituitary-ovarian axis, this axis controls secretion of female reproductive hormones such as follicle-stimulating hormone (FSH) and luteinizing hormone (LH). It was mentioned by Mastorakos et al. that strenuous exercise is related with a decreased hypothalamic-pituitary-adrenal secretion. The stress of exercise can stop the gonadal function, by the production of glucocorticoids and cathecholamines with activation of the corticotropin releasing hormone neurons. Additionally, it was mentioned by Warren & Perlroth  that low caloric input and high caloric expenditure can result in endocrine abnormalities, and this could be a factor which affects gonadotropin-releasing hormone suppression that manifests as menstrual disturbances with strenuous training. The consequence effects of strenuous exercise on female menstrual dysfunction consist of amenorrhea, infertility and osteoporosis.
Honey is a natural product with high concentrated solution of a complex mixture of sugars that has been widely used for its therapeutic effect. Honey contains about 200 substances such as sugar (fructose, glucose, maltose and sucrose), enzymes, flavonoids, minerals, organic acids, proteins, phenolic acids and vitamins . Tualang honey which was used in the present study is a type of wild multiflora honey found in the Malaysian rain forest which contains phenolic compounds that possess relatively good antioxidant activity using 1,1-diphenyl-2-picrylhydrazil (DPPH) and ferric chloride antioxidant power (FRAP) assays, which is comparable with other reported honeys such as Romanian and Slovenian honeys . Chepulis and Starkey  reported that honey feeding alone has shown its beneficial effects on bone mineral density in animals. Additionally, two previous studies have shown that honey has similar effects with hormone replacement therapy on bone densitometry  and prevents uterine atrophy in postmenopausal state . Nevertheless, these previous studies did not report the underlying mechanisms that could explain the increase in bone mass by honey feeding.
Recently, it has been reported that honey supplementation of 1 g/kg body weight, 7 days/week combined with moderate jumping exercise intensity of 40 jumps/day, 5 days/week for 8 weeks may elicit beneficial effects on bone in young female rats [5, 26]. Nevertheless, the effects of honey supplementation combined with other lower or higher jumping exercise intensities have not been investigated. A recent study done by Mohamed et al. showed that honey significantly attenuated the toxic effects of cigarette smoke on spermatogenesis and testosterone level in male rats. Their study finding implies that honey might elicit protective effect against cigarette smoke-induced impaired testicular functions, and it may have a protective effects on disturbance of reproductive hormones in male rats. However, to date no study has been carried out to investigate whether combination of higher intensity of jumping exercise with honey may elicit different effects on bone health and gonadotropins compared to combination of lower intensity of jumping exercise with honey in female rats. Moreover, we hypothesize that honey as a source of energy and its antioxidant properties may protect against adverse effects induced by exercise on gonadotropin hormones. Therefore, the aim of this study was to investigate the effects of different jumping exercise intensities, i.e. low and high intensities combined with honey supplementation on bone parameters and gonadotropins in female rats.
Eighty four, 9-week old female Sprague–Dawley rats with initial body weight of 175–210 g were obtained from the Animal Research and Service Center, Universiti Sains Malaysia (USM). The experimental protocol was approved by Animal Ethics Committee, Universiti Sains Malaysia (USM/Animal Ethics Approval 2011/ ). Standard chow in pellet form (Gold Coin, Port Klang, Malaysia), and water were provided ad libitum to all rats in all groups throughout the study.
Vaginal smear and body weight measurement
At the beginning and end of this study, vaginal smear was performed on diestrus phase for standardization to make sure that the rats started and ended the experiment at same hormonal phase. Vaginal secretion of each rat was collected with a plastic pipette filled with 10 μL of normal saline (NaCl 0.9%) by inserting the pipette tip into the rat vagina, then unstained materials were observed under a light microscope at 100 x magnification. Initial body weights were measured to the nearest 0.1 g by using a body weight weighing scale (NavigatorTM, OHAUS Corporation, N2B110, Switzerland).
After initial body weight measurement and vaginal smear, the rats were block-randomised into 7 initial body-weigh-matched groups with 12 rats per each group: Baseline control that were sacrificed at 9 week-old at the beginning of the study (C0), sedentary group without supplementation and exercise with free cage activity for 8 weeks (C), low intensity jumping exercise with 20 jumps per day at 5 days per week for 8 weeks (J20), high intensity jumping exercise with 80 jumps per day for 5 days per week for 8 weeks (J80), honey supplementation for 7 days per week for 8 weeks (H), low intensity of 20 jumps per day for 5 days per week combined with honey supplementation for 8 weeks (HJ20), high intensity of 80 jumps per day for 5 days per week combined with honey supplementation for 8 weeks (HJ80).
Honey supplementation was given to the rats with a dosage of 1 g per kg body weight per day by oral gavage force fed for 7 days per week. The prescribed honey dosage was based on Tavafzadeh . The rats in combined honey with jumping exercise group (HJ20 & HJ80) were fed with honey, 30 minutes prior to the jumping exercise session. The dosage of honey was calculated based on the rat biweekly body weight .
The training programme of this study was done 5 days per week according to the previous study , and consisted of 20 and 80 jumps per day for 8 weeks. Briefly, each rat in the jumping exercise groups was placed at the bottom of a specially designed wooden box, measuring 30.5 cm × 30.5 cm and 40 cm in length, width and height, respectively. The jumping exercise was initiated by applying an electrical current to the wired floor (electrical grid) of the box through a stimulator. When stimulated, each rat jumped from the floor of the box to catch the top edge of the box with its forepaws. The rat was then immediately returned to the floor of the box to repeat the procedure. The time required per jump was about 4 seconds. After a few days of training, the rats jumped without electrical stimulation. Rats in the sedentary groups were not given any electrical stimulus but to mimic the stress induced by handling, before and after jumping exercise, the sedentary rats were also just handled during the duration of the study.
Blood collection and analysis
At the end of the experimental period, the rats were anaesthetised by lying for 2–3 minutes in a dried jar containing chloroform-soaked gauze pad, then they were decapitated by using a small guillotine (Scientific Research Instrument, UK). Blood from the decapitated site was collected into the 10 mL test-tube through a funnel, it was allowed to completely clotted and subsequently centrifuged at 4°C and 4000 RPM for 15 minutes (Health-Ratina 46RS, Germany). Serum was collected and stored under temperature of −80°C (Heto Ultra Freezer 3410, Denmark) for subsequent analysis of serum total calcium (Ca), serum alkaline phosphatase (ALP), serum C-terminal telopeptide of type 1 collagen (1CTP), serum follicle stimulating hormone (FSH) and serum luteinizing hormone (LH).
Levels of serum total calcium, serum alkaline phosphatase, serum C-terminal telopeptide type 1 collagen, serum follicle-stimulating hormone and serum luteinizing hormone were measured using commercial kits (Ca: Randox, UK; ALP: AMP Buffer, UK; 1CTP: Creative diagnostic ELISA Kit, USA; Rat FSH: Cusbio ELISA Kit, USA; LH: Cusbio ELISA Kit, USA).
The intra-assay coefficient of variation (CV) of the assay kits were 0.9%, 0.7% and 0.4% at 2.12, 2.29 and 3.32 mmol.l−1 of serum total calcium concentration respectively, and the interassay CV were 1.5%, 1.6% and 0.8% at 2.10, 2.28 and 3.28 mmol.l−1 of serum total calcium concentration respectively. For serum alkaline phosphatase, the intraassay coefficient of variation (CV) of the assay kits were 0.67%, 0.47%, 0.45% and 0.61% at 63.3, 84.1, 214.7 and 304.7 U/L -1 of serum alkaline phosphatase concentration respectively, and the interassay CV were 0.67%, 0.27%, 0.47% and 0.67% at 62.0, 85.6, 210.6 and 298.3 U/L -1 of serum alkaline phosphatase concentration respectively. For both serum follicle-stimulating hormone (FSH) and luteinizing hormone (LH), the intra- and inter assay precision within an assay was less than 15%. The detection range of the assay kits of serum 1CTP was 0.156-10 ng/mL, and the minimum detectable dose of serum 1CTP was less than 0.03 ng/mL.
The left hind legs (tibia and femur) of the rats were dissected and the fleshy tissues were cleaned from the tibia and femur. Bone mass; i.e. tibial and femoral wet weights were measured using an electronic balance (Denver Instrument Company, AA-160 USA) . Subsequently, tibia and femur were then immersed in a mixture of chloroform and methanol solvent (2:1 by volume respectively) for one week to remove the fat from the bones. Following this, the bones were oven dried at 80ºC for 24 hours (Isuzu Model 2–2020, Isuzu Seisakusho Co., Ltd., Japan). After drying, the fat free dry weight (to the nearest 0.01 mg) was determined on an electronic balance (ER-180A, A&D Company, Japan). Bone fat free dry weight is an indicator of bone mass, where it refers to bone weight with only the solid composition, i.e. mineral and organic (matrix) phases of the bone.
Statistical analysis was performed by using the Statistical Package of Social Sciences (SPSS) Version 18.0. The power of the study was set at 80% with 95% confidence interval. All the data are presented as mean [95% confidence interval]. After checking normality and homogeneity, the data with normal distribution and homogenous variances were analysed using one-way analysis of variance (ANOVA) to determine the significance of the difference between groups. Whilst the One-way ANOVA revealed a significant difference, post hoc (least significant differences test) was used to determine the differences between specific means. The P value of <0.05 was considered as statistically significant and used for all the comparisons.
Initial and final body weights, left tibial and femoral wet and fat free dry weights of the rats
Initial body weight (g)
Final body weight (g)
Tibial wet weight (mg)
Tibial fat free dry weight (mg)
Femoral wet weight (mg)
Femoral fat free dry weight (mg)
Bone metabolism markers: serum total calcium (Ca), serum alkaline phosphatase (ALP) and serum C-terminal telopeptide of type 1 collagen (1CTP)
1CTP (ng/ mL)
Serum follicle stimulating hormone (FSH) and serum luteinizing hormone (LH)
The present study found that training regimen of high intensity jumping exercise containing 80 jumps per day combined with 1 g per kg body weight of daily honey supplementation elicited more discernable beneficial effects on tibial and femoral mass compared to low intensity jumping exercise containing 20 jumps per day combined with honey supplementation, jumping exercise alone and honey supplementation alone in young female rats. We observed that bone wet and fat free dry weights as indicators of bone mass with both organic and mineral phases in high intensity jumping combined with honey supplementation group was significantly greater than all the other experimental groups. Meanwhile honey supplementation alone, and both low and high intensity jumping exercises with or without honey supplementation elicited beneficial effects on enhancing bone mass compared to sedentary without honey supplementation control rats. The present study also showed that high intensity jumping exercise combined with honey may elicit more beneficial effects on tibial mass compared to low intensity jumping exercise combined with honey supplementation.
The osteogenic effects of mechanical loading have been manifested by many studies. Loading is known as an essential factor in the bone formation . Forwood  has suggested that mechanical loads greater than common force which met by skeleton can increase bone mass as result of increasing bone formation and reduction of bone turnover. It has been proven by animal studies that jump exercise as a high impact loading exercise model gives large ground reaction and muscular contraction forces to lower limb bones during landing [3, 30]. Similarly, the present study finding was consistent with previous jumping exercise studies which reported positive effects of this type of exercise on bone mass in rats [3, 5]. It is postulated that the rhythmic nature of dynamic loading in this type of high impact loading exercise may increase delivered blood volume to working muscle compared to low impact loading exercise , therefore beneficial effects on bone mass was observed in the present study. It was reported in a previous study that bone mass increased significantly with only 5 or 10 jumps per day, and high amount of loadings per day was not necessarily for increasing bone health . Two other human studies also showed the efficiency of high-impact and low-repetition exercises on bone mineral density [32, 33]. Our results are in agreement with these aforementioned previous studies with the evidences that jumping exercise as low as 20 jumps per day at 5 days per week for 8 weeks may have potential to increase bone mass in young rats.
Regarding the present positive finding of honey supplementation on bone mass, it was reported that ingestion of carbohydrates is effective in increasing calcium absorption and suppressing bone resorption in human  and animal , implying that carbohydrate ingestion may enhance bone mineralization and organic matrix reflected by increased bone mass, as observed in the present study among honey fed rats. In a previous study, Ariefdjohan and colleagues  have shown that acute feeding of honey could increase calcium absorption in rats. Therefore the finding of large increased in bone mass as shown by the great increased bone wet weight in rats with combination of honey supplementation and high intensity of 80 jumps per day in this study might be due to increased calcium absorption with honey supplementation. The present finding may reflect that high intensity jumping exercise with 80 jumps per day combined with honey supplementation could cause enhancement of blood flow to working muscle for supplying nutrients contained in honey such as calcium, phosphorus, magnesium and vitamins to the bone during exercise.
Regarding bone metabolism markers, it was found that serum total calcium was significantly higher in high intensity jumping combined with honey supplementation than honey alone group. This observation implies that 80 jumps per day combined with honey feeding were most effective in enhancing serum total calcium level in the rats. It is speculated that honey feeding and its carbohydrate constituents such as glucose, fructose, and raffinose enhanced calcium absorption from intestinal tract  through the large volume of blood delivered to the muscle and subsequently to the bone by performing jumping exercise .
Serum alkaline phosphatase, a bone formation marker, was significantly greater in high exercise intensity combined with honey group and honey supplementation alone group compared to sedentary without honey supplementation controls. Additionally, serum alkaline phosphatase was significantly higher in low and high intensity jumping exercise combined with honey supplementation group and honey supplementation group compared to low intensity jumping exercise alone group. It seems that jumping exercise in both high and low levels of intensity combined with honey supplementation may elicit beneficial effects on bone by increasing level of bone formation marker, nevertheless, more discernable effect was observed in combined 80 jumps per day with honey group. The positive finding in combined 80 jumps per day with honey group in serum formation marker was consistent with serum total calcium mentioned earlier. In a recent human study carried out by the present researcher, it was also observed that aerobic dance exercise combined with honey supplementation could increase level of bone formation marker in young woman . Interestingly, the present study also found that honey supplementation alone was effective in increasing serum alkaline phosphatase, this observation may reflect that the vital components contained in honey such as sugar, i.e. fructose, glucose, maltose and sucrose; enzymes, flavonoids, minerals, oxidants, organic acids, proteins, phenolic acids and vitamins  may have played their roles in enhancing bone formation.
In bone resorption marker, it was evidenced in the present study that serum 1CTP levels were significantly lower in honey alone group, low and high intensity jumping exercise alone groups and combined 20 and 80 jumps per day with honey group when compared to sedentary without honey supplementation control group. Nevertheless, combined 80 jumps per day with honey group elicited more discernable effect on reducing the level of serum bone resorption marker than 20 jumps per day combined with honey supplementation.
The beneficial effects of honey alone on bone resorption revealed that the vital components contained in honey such as carbohydrates, minerals, vitamins and flavonoids  may have potential in reducing bone resorption in the present study. Similar findings of reduction of bone resorption marker as results of exercise as observed in the present study has been reported by Kishimoto et al. which found that 10 jumps per day for 5 days per week decreased level of serum 1CTP after 2 weeks of training in female college-aged non-athletes. We also found that combined 80 jumps per day with honey elicited discernable effect on reducing the level of serum 1CTP. Nevertheless, a recent human study done by Ooi et al. found that aerobic dance exercise consisted of 1 hour per day, 3 times per week combined with 20 g of Gelam honey for 7 days per week for a duration of 6 weeks did not show any significant effect on serum C-terminal telopeptide of type 1 collagen level in young female. The discrepancy between the present study and the aforementioned previous study results maybe due to variation in type and duration of the physical trainings and kind of recruited subjects in both studies. The reduction in bone resorption marker in combined exercise with honey group of the present study may be due to the effect of jumping exercise on enhancement of blood volume and osteoblastic activity, and there was suppression of parathyroid hormone-vitamin D mechanism subsequent of increased calcium absorption after honey feeding . Additionally, it was reported by previous studies that kaempferol, a flavonoid, has osteogenic and anti-osteoclastogenic effects on rats [40, 41]. Flavonoid is effective in bone loss reduction by increase the numbers of osteoprogenitor cells and inhibit osteoclastic activity . Therefore, the significant reduction in bone resorption marker in combined honey with jumping exercise group may be due to increase in supply of flavonoids component of Tualang honey, i.e. kaempferol  through the increased of blood flow to the working muscle induced by jumping exercise.
In the present study, levels of FSH were lower in low and high intensity jumping exercise alone groups and honey supplementation alone group compared to sedentary without honey supplementation control group. However, there were no significant differences in both combined low and high intensity jumping with honey groups compared to sedentary without honey supplementation control group. These findings imply that honey combined with low and high intensity jumping exercise can maintain FSH level as sedentary without honey supplementation group. In a human study done by Valentino et al. , it was reported that intense ballet training was accompanied with lower level of reproductive hormone, i.e. FSH in young women. Meanwhile, it was reported by Williams and colleagues  that low energy availability and negative energy balance, i.e. dietary energy intake minus exercise energy expenditure following vigorous and regular exercise regimen reduces gonadotrophins secretion from anterior pituitary gland via hypothalamic-pituitary pathway. They have shown that calories supplementation which contained one quarter piece of fresh fruit, i.e. 25 kcal that was equal to 138–181% of calorie intake, during amenorrhea induced by strenuous exercise, caused increases in reproductive hormone levels, i.e. FSH and LH, and reestablished ovulatory cycles in female cynomolgus monkeys. Their finding confirmed that exercise-induced suppression of reproductive function is caused by the energy expenditure associated with vigorous regular exercise.
Our data revealed that honey supplementation alone was accompanied with low level of FSH. Similarly, Zaid et al. reported that administration of low dose of 0.2 g per kg, medium dose of 1.0 g per kg and high dose of 2.0 g per kg Tualang honey were accompanied with nonsignificant lower level of serum FSH in honey treatment groups compared to ovariectomised control rats. The present study found that both low and high intensities of jumping exercise may have elicited negative effects on FSH level and the combination of honey supplementation and exercise in both levels of intensities could improve the adverse effects induced by jumping exercise on FSH level.
In the present study, LH level was significantly lower in all the experimental groups compared to sedentary without supplementation control group, with exception of higher intensity jumping exercise combined with honey and lower intensity jumping exercise. Moreover, level of LH were significantly higher in both higher and lower intensities jumping combined with honey and lower intensity jumping compared to high intensity jumping without honey supplementation. As we explained before, exercise especially high intense exercise can affect release of the amount of hypothalamic hormone and reduction in the level of gonadotrophins, i.e. LH [44, 45]. It was also reported that restricted energy avaibility due to intense exercise via disruption in gonadotropin releasing hormone can cause reduction in LH concentration in female [43, 46]. In the present study, lower level of serum LH in the rats of honey supplementation group compared to sedentary without supplementation group may be implies that rats in the honey group were under stress due to force feeding and honey alone did not have protective effects on luteinizing hormone. Nevertheless, the precise mechanism of lower level of LH in HJ20 group compared to sedentary group is unknown and further investigation is needed. The present finding of lower level of serum LH in the J80 compared to J20, HJ20 and HJ80 implied that high intensity jumping exercise without honey supplementation may have elicited negative effects on serum LH. This result implies that honey, a high concentrated source of energy with 313 calories per 100 g and antioxidants such as flavonoids and phenolic acid  may have potential to elicit beneficial effects on reduction of adverse effect induced by high intensity jumping exercise.
Body composition such as fat or muscle mass are potent stimulators of bone mass. One of the limitations of the present study was that fat mass was not measured, and the lower limb muscle of the rats were not collected and weighed for adjusting the bone mass value of the rats. The present finding may reflect the potential use of honey for maintaining bone health and reproductive functions. However, it is suggested to monitor insulin sensitivity for detecting the possible metabolic side effects due to an overload of sugar amount for those who are supplemented with honey in their daily life. Nevertheless, further studies are needed to elucidate the exact mechanism of honey in improving bone metabolism and reproductive hormone levels.
In conclusion, high intensity jumping exercise combined with honey may elicit beneficial effects on bone mass and bone metabolism markers. In addition, honey could elicit protective effects on disturbance of reproductive hormone levels induced by high and low intensities of jumping exercise. Therefore, honey may be able to be recommended to female athletes for maintaining their bone health and normal reproductive functions.
The authors would like to acknowledge Universiti Sains Malaysia for providing the research grant (No: 304 /PPSP/61312031). The authors would like to thank Ms. Jamaayah bt Meor Osman, Mr. Mohd Nizam Haron, Ms. Somayeh Sadat Tavafzadeh, Miss Nor Aini bt Sudin, Ms Nurul Nabillah binti Hasbullah and Ms Parimalah Velo for their assistance in this study.
- Berard A, Bravo G, Gauthier P: Meta-analysis of the effectiveness of physical activity for the prevention of bone loss in postmenopausal women. Osteoporos Int. 1997, 7: 331-337. 10.1007/BF01623773.View ArticlePubMedGoogle Scholar
- Maimoun L, Manetta J, Couret I, Dupuy A, Mariano-Goulart D, Micallef J, Peruchon E, Rossi M: The intensity level of physical exercise and the bone metabolism response. Int J Sports Med. 2006, 27: 105-111. 10.1055/s-2005-837621.View ArticlePubMedGoogle Scholar
- Umemura Y, Ishiko T, Yamauchi T, Kurono M, Mashiko S: Five jumps per day increase bone mass and breaking force in rats. J Bone Miner Res. 1997, 12: 1480-1485. 10.1359/jbmr.19126.96.36.1990.View ArticlePubMedGoogle Scholar
- Ooi FK, Singh R, Singh HJ, Umemura Y: Minimum level of jumping exercise required to maintain exercise-induced bone gains in female rats. Osteoporos Int. 2009, 20: 963-972. 10.1007/s00198-008-0760-6.View ArticlePubMedGoogle Scholar
- Tavafzadeh SS, Ooi FK, Oleksandr K, Sulaiman S: Effect of a combination of jumping exercise and honey supplementation on the mass, strength and physical dimensions of bones in young female rats. J ApiProduct ApiMedical Sci. 2011, 3: 26-32. 10.3896/IBRA.4.03.1.05.View ArticleGoogle Scholar
- McKay HA, Petit MA, Schutz RW, Prior JC, Barr SI, Khan KM: Augmented trochanteric bone mineral density after modified physical education classes: a randomized school-based exercise intervention study in prepubescent and early pubescent children. J Pediatr. 2000, 136: 156-162. 10.1016/S0022-3476(00)70095-3.View ArticlePubMedGoogle Scholar
- MacKelvie KJ, McKay HA, Khan KM, Crocker PRE: A school-based exercise intervention augments bone mineral accrual in early pubertal girls. J Pediatr. 2001, 139: 501-508. 10.1067/mpd.2001.118190.View ArticlePubMedGoogle Scholar
- Petit MA, McKay HA, MacKelvie KJ, Heinonen A, Khan KM, Beck TJ: A randomized school-based jumping intervention confers site and maturity-specific benefits on bone structural properties in girls: a hip structural analysis study. J Bone Miner Res. 2002, 17: 363-372. 10.1359/jbmr.2002.17.3.363.View ArticlePubMedGoogle Scholar
- Petterson U, Nordstrőm P, Alfredson H, Henriksson-Larsén K, Lorentzon R: Effect of high impact activity on bone mass and size in adolescent females: a comparative study between two different types of sports. Calcif Tissue Int. 2000, 67: 207-214. 10.1007/s002230001131.View ArticleGoogle Scholar
- Witzke KA, Snow CM: Effects of plyometric jump training on bone mass in adolescent girls. Med Sci Sports Exerc. 2000, 32: 1051-1057.View ArticlePubMedGoogle Scholar
- Matsuda JJ, Zernicke RF, Vailas AC, Pedrini VA, Pedrini-Mille A, Maynard JA: Structural and mechanical adaptation of immature bone to strenuous exercise. J Appl Physiol. 1986, 60: 2028-2034.PubMedGoogle Scholar
- Hou CH, Salem GJ, Zernicke RF, Barnard RJ: Structural and mechanical adaptations of immature trabecular bone to strenuous exercise. J Appl Physiol. 1990, 69: 1309-1314.PubMedGoogle Scholar
- Li KC, Zernicke RF, Barnard RJ, Li AF: Differential response of rat limb bones to strenuous exercise. J Appl Physiol. 1991, 70: 554-560. 10.1063/1.349655.View ArticlePubMedGoogle Scholar
- Maynard JA, Pedrini-Mille A, Pedrini VA, Vailas AC: Morphological and biochemical effects of strenuous exercise on immature long bones. Iowa Orthop J. 1995, 15: 162-167.PubMedPubMed CentralGoogle Scholar
- Carlberg KA, Buckman MT, Peake GT, Riedesel ML: A survey of menstrual function in athletes. Eur J Appl Physiol Occup Physiol. 1983, 51: 211-222.View ArticleGoogle Scholar
- Barrow GW, Saha S: Menstrual irregularity and stress fractures in collegiate female distance runners. Am J Sports Med. 1988, 16: 209-216. 10.1177/036354658801600302.View ArticlePubMedGoogle Scholar
- Castelo-Branco C, Reina F, Montivero AD, Colodrón M, Vanrell JA: Influence of high-intensity training and dietetic and anthropometric factors on menstrual cycle disorders in ballet dancers. Gynecol Endocrinol. 2006, 22: 31-35. 10.1080/09513590500453825.View ArticlePubMedGoogle Scholar
- Valentino R, Savastano S, Tommaselli AP, D’Amore G, Dorato M, Lombardi G: The influence of intense ballet training on trabecular bone mass, hormone status, and gonadotropin structure in young women. J Clin Endocrinol Metab. 2001, 86: 4674-4678. 10.1210/jcem.86.10.7908.View ArticlePubMedGoogle Scholar
- Mastorakos G, Pavlatou M, Diamanti-Kandarakis E, Chrousos GP: Exercise and the stress system. Horm. 2005, 4: 73-89.Google Scholar
- Warren MP, Perlroth NE: The effects of intense exercise on the female reproductive system. J Endocrinol. 2001, 170: 3-11. 10.1677/joe.0.1700003.View ArticlePubMedGoogle Scholar
- Aljadi A, Kamaruddin M: Evaluation of the phenolic contents and antioxidant capacities of two Malaysian floral honeys. Food Chem. 2004, 85: 513-518. 10.1016/S0308-8146(02)00596-4.View ArticleGoogle Scholar
- Mohamed M, Sirajudeen K, Swamy M, Yaacob NS, Sulaiman SA: Studies on the antioxidant properties of Tualang honey of Malaysia. Afr J Tradit Complement Altern Med. 2010, 7: 59-63. 10.1625/jcam.7.59.Google Scholar
- Chepulis L, Starkey N: The long term effects of feeding honey compared with sucrose and a sugar free diet on weight gain, lipid profiles, and DEXA measurements in rats. J Food Sci. 2008, 73: H1-H7. 10.1111/j.1750-3841.2007.00641.x.View ArticlePubMedGoogle Scholar
- Hussain NHN, Sulaiman SA, Hassan II, Kadir AA, Nor NM, Ismail SB, Yaacob LH, Zakaria R, Shafie NS, Haron J: Randomized controlled trial on the effects of tualang honey and hormonal replacement therapy (HRT) on cardiovascular risk factors, hormonal profiles and bone density among postmenopausal women: a pilot study. J Food Res. 2012, 1: 171-188.Google Scholar
- Zaid SSM, Sulaiman SA, Sirajudeen KNM, Othman NH: The effects of Tualang honey on female reproductive organs, tibia bone and hormonal profile in ovariectomised rats-animal model for menopause. BMC Complement Altern Med. 2010, 10: 1-7. 10.1186/1472-6882-10-1.View ArticleGoogle Scholar
- Ooi FK, Tavafzadeh SS, Oleksandr K, Sulaiman SA, Chan KM, Hung LK, Hung WY: Combined jumping exercise and honey supplementation enhance tibial moment of inertia and maximum force in young female rats. Osteoporos Int. 2010, 21: S675-S772.View ArticleGoogle Scholar
- Mohamed M, Sulaiman SA, Jaafar H, Sirajudeen KNS: Antioxidant protective effect of honey in cigarette smoke-induced testicular damage in rats. Int J Mol Sci. 2011, 12: 5508-5552. 10.3390/ijms12095508.View ArticlePubMedPubMed CentralGoogle Scholar
- Gross TS, Edwards JL, Mcleod KJ, Rubin CT: Strain gradients correlate with sites of periosteal bone formation. J Bone Miner Res. 1997, 12: 982-988. 10.1359/jbmr.19188.8.131.522.View ArticlePubMedGoogle Scholar
- Forwood M: Mechanical effects on the skeleton: are there clinical implications?. Osteoporos Int. 2001, 12: 77-78. 10.1007/s001980170161.View ArticlePubMedGoogle Scholar
- Umemura Y, Nagasawa S, Honda A, Singh R: High-impact exercise frequency per week or day for osteogenic response in rats. J Bone Miner Metab. 2008, 26: 456-460. 10.1007/s00774-007-0848-7.View ArticlePubMedGoogle Scholar
- Ooi FK, Singh R, Singh HJ: Jumping exercise and bone health:beneficial effects of jumping exercise on bone health. 2009, Germany: VDM Verlag Dr. MullerGoogle Scholar
- Kato T, Terashima T, Yamashita T, Hatanaka Y, Honda A, Umemura Y: Effect of low-repetition jump training on bone mineral density in young women. J Appl Physiol. 2006, 100: 839-843.View ArticlePubMedGoogle Scholar
- Macdonald HM, Kontulainen SA, Khan KM, McKay HA: Is a school based physical activity intervention effective for increasing tibial bone strength in boys and girls?. J Bone Miner Res. 2006, 22: 434-446.View ArticleGoogle Scholar
- Griffin I, Davila P, Abrams S: Non-digestible oligosaccharides and calcium absorption in girls with adequate calcium intakes. Br J Nutr. 2002, 87: S187-S191. 10.1079/BJN/2002536.View ArticlePubMedGoogle Scholar
- Zafar TA, Weaver CM, Zhao Y, Martin BR, Wastney ME: Nondigestible oligosaccharides increase calcium absorption and suppress bone resorption in ovariectomized rats. J Nutr. 2004, 134: 399-402.PubMedGoogle Scholar
- Ariefdjohan MW, Martin BR, Lachcik PJ, Weaver CM: Acute and chronic effects of honey and its carbohydrate constituents on calcium absorption in rats. J Agric Food Chem. 2008, 56: 2649-2654. 10.1021/jf073357w.View ArticlePubMedGoogle Scholar
- Ooi FK, Ismail N, Abdullah MY: Effects of combined aerobic dance exercise and honey supplementation on bone turnover markers in young females. Asian J Exerc Sport Sci. 2011, 8: 1-11.Google Scholar
- Kishimoto K, Lynch RP, Reiger J, Yingling VR: Short-term jump activity on bone metabolism in female college-aged non-athletes. J Sports Sci Med. 2012, 11: 31-38.PubMedPubMed CentralGoogle Scholar
- Brommage R, Binacua C, Antille S, Carrié AL: Intestinal calcium absorption in rats is stimulated by dietary lactulose and other resistant sugars. J Nutr. 1993, 123: 2186-2194.PubMedGoogle Scholar
- Wattel A, Kamel S, Mentaverri R, Lorget F, Prouillet C, Petit JP, Fardelonne P, Brazier M: Potent inhibitory effect of naturally occurring flavonoids quercetin and kaempferol on in vitro osteoclastic bone resorption. Biochem Pharmacol. 2003, 65: 35-42. 10.1016/S0006-2952(02)01445-4.View ArticlePubMedGoogle Scholar
- Trivedi R, Kumar S, Kumar A, Siddiqui JA, Swarnkar G, Gupta V, Kendurker A, Dwivedi AK, Romero JR, Chattopadhyay N: Kaempferol has osteogenic effect in ovariectomized adult Sprague–Dawley rats. Mol Cell Endocrinol. 2008, 289: 85-93. 10.1016/j.mce.2008.02.027.View ArticlePubMedGoogle Scholar
- Khalil MI, Alam N, Moniruzzaman M, Sulaiman SA, Gan SH: Phenolic acid composition and antioxidant properties of Malaysian honeys. J Food Sci. 2011, 76: C921-C928. 10.1111/j.1750-3841.2011.02282.x.View ArticlePubMedGoogle Scholar
- Williams NI, Helmreich DL, Parfitt DB, Caston-Balderrama A, Cameron JL: Evidence for a causal role of low energy availability in the induction of menstrual cycle disturbances during strenuous exercise training. J Clin Endocrinol Metab. 2001, 86: 5184-5193. 10.1210/jcem.86.11.8024.View ArticlePubMedGoogle Scholar
- Cumming DC, Vickovic MM, Wall SR, Fluker MR, Belcastro AN: The effect of acute exercise on pulsatile release of luteinizing hormone in women runners. Am J Obstet Gynecol. 1985, 153: 482-485. 10.1016/0002-9378(85)90457-0.View ArticlePubMedGoogle Scholar
- De Souza MJ, Miller BE, Loucks AB, Luciano AA, Pescatello LS, Campbell CG, Lasley BL: High frequency of luteal phase deficiency and anovulation in recreational women runners: blunted elevation in follicle-stimulating hormone observed during luteal-follicular transition. J Clin Endocrinol Metab. 1998, 83: 4220-4232.PubMedGoogle Scholar
- Loucks AB, Verdun M, Heath EM: Low energy availability, not stress of exercise, alters LH pulsatility in exercising women. J Appl Physiol. 1998, 84: 37-46.PubMedGoogle Scholar
- The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1472-6882/14/126/prepub
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.