Category Archives: Exercise

Judo Provides Powerful Oseogenic Stimuli Despite Off-Season Weight Loss

Abstract

Bone density in elite judoists and effects of weight cycling on bone metabolic balance.

Weight cycling has been shown to exert negative effects on bone metabolism and bone mass, whereas weight-bearing activity is positively associated with bone mineral density (BMD). Bone health in judoists and effects of weight cycling on bone metabolism have not previously been investigated. To examine potential disrupter and stimulators of bone integrity, this study analyzed bone parameters at baseline and the effects of the first weight cycle of the season on bone metabolic status in 48 male and female elite judoists.
Body composition and lumbar, femoral, and total body BMD were evaluated by dual-energy x-ray absorptiometry. Cortisol, osteocalcin, C-terminal telopeptide of type I collagen (CTx), and bone uncoupling index (UI) were measured in judoists at normal body weight, after weight reduction, and after regaining weight. As a comparison, a control group of moderately active students was included at baseline. Training, menstrual status, and calcium intake were assessed by questionnaires.
Euweighted judoists displayed high BMD and an increased rate of bone formation. Precompetitive weight loss averaged 4 +/- 0.3% of body weight and induced an acute rise in cortisol (81%, P < 0.05) and CTx (33%, P < 0.0001), with a metabolic imbalance in favor of bone resorption. A 4 +/- 0.5% weight regain restored a positive UI in favor of bone formation. Metabolic responses were not dependent on gender. BMD was unaltered by weight cycling.
Increased bone formation rate pertaining to judo athletes lent protection from alterations in bone metabolic balance associated with weight cycling. This observation suggests that powerful osteogenic stimuli provided by judo’s unique biomechanical environment may help prevent bone loss associated with weight loss.

Prouteau S, Pelle A, Collomp K, Benhamou L…
Med Sci Sports Exerc Apr 2006
PMID: 16679985

Comment: Cycling and bone health: a systematic review

Abstract

Bike racing, recreational riding, impact sport and bone health.

Cycling has been shown to confer considerable benefits in terms of health, leading to reductions in death rates principally due to cardiovascular improvements and adaptation. Given the disparity between the benefits of cycling on cardiovascular fitness and previous research finding that cycling may not be beneficial for bone health, Hugo Olmedillas and colleagues performed a systematic review of the literature. They concluded that road cycling does not appear to confer any significant osteogenic benefit. They postulate that the cause of this is that, particularly at a competitive level, riders spend long periods of time in a weight-supported position on the bike. Training programs may be supplemented with impact loading to preserve bone health; however, the small increased risk of soft tissue injury must also be considered. See related study.

Carmont MR
BMC Med 2012
PMID: 23256478 | Free Full Text

Review: Cyclists Have Low Bone Density

Abstract

Cycling and bone health: a systematic review.

Cycling is considered to be a highly beneficial sport for significantly enhancing cardiovascular fitness in individuals, yet studies show little or no corresponding improvements in bone mass.
A scientific literature search on studies discussing bone mass and bone metabolism in cyclists was performed to collect all relevant published material up to April 2012. Descriptive, cross-sectional, longitudinal and interventional studies were all reviewed. Inclusion criteria were met by 31 studies.
Heterogeneous studies in terms of gender, age, data source, group of comparison, cycling level or modality practiced among others factors showed minor but important differences in results. Despite some controversial results, it has been observed that adult road cyclists participating in regular training have low bone mineral density in key regions (for example, lumbar spine). Conversely, other types of cycling (such as mountain biking), or combination with other sports could reduce this unsafe effect. These results cannot yet be explained by differences in dietary patterns or endocrine factors.
From our comprehensive survey of the current available literature it can be concluded that road cycling does not appear to confer any significant osteogenic benefit. The cause of this may be related to spending long hours in a weight-supported position on the bike in combination with the necessary enforced recovery time that involves a large amount of time sitting or lying supine, especially at the competitive level.

Olmedillas H, González-Agüero A, Moreno LA, Casajus JA…
BMC Med 2012
PMID: 23256921 | Free Full Text

Video: Dr. Hofflich “Osteoporosis Update 2013” – Stein Institute for Research on Aging

Here is a nice talk by Dr. Heather Hofflich from May 15, 2013. She’s an Associate Professor of Medicine at UCSD. She gives an overview of osteoporosis and discusses the causes and therapies used to treat it. She also takes a look at recent controversies in treatment plans and vitamin usage.

One thing that bothers me about her talk is that she claims Teriparatide is the only thing in the world that builds bone by increasing osteoblast activity. I’ve posted many studies that found increases in osteoblasts from a variety of things. She also didn’t mention any other potentially helpful dietary supplements besides Calcium and Vitamin D. Like most MDs, she is probably unaware of anything that is not FDA approved.

Review: Cardiovascular Disease and Osteoporosis Strategies

Abstract

Cardiovascular disease and osteoporosis: balancing risk management.

In this narrative review of the current literature, we examine the traditional risk factors and patient profiles leading to cardiovascular disease and osteoporosis. We discuss the interrelationships between risk factors and common pathophysiological mechanisms for cardiovascular disease and osteoporosis. We evaluate the increasing evidence that supports an association between these disabling conditions. We reveal that vascular health appears to have a strong effect on skeletal health, and vice versa. We highlight the importance of addressing the risk benefit of preventative interventions in both conditions. We discuss how both sexes are affected by these chronic conditions and the importance of considering the unique risk of the individual. We show that habitual physical activity is an effective primary and secondary preventative strategy for both cardiovascular disease and osteoporosis. We highlight how a holistic approach to the prevention and treatment of these chronic conditions is likely warranted.

Warburton DE, Nicol CW, Gatto SN, Bredin SS
Vasc Health Risk Manag 2007
PMID: 18078019 | Free Full Text

Protein + Exercise Improves Bone Markers in Young Adults

Abstract

Effect of protein supplementation during a 6-mo strength and conditioning program on insulin-like growth factor I and markers of bone turnover in young adults.

Exercise is beneficial for bone when adequate nutrition is provided. The role of protein consumption in bone health, however, is controversial. The objective was to ascertain the effect of high protein intake on insulin-like growth factor I (IGF-I) and markers of bone turnover during 6 mo of exercise training. Fifty-one subjects aged 18-25 y (28 men, 23 women) received a protein supplement (42 g protein, 24 g carbohydrate, 2 g fat) or a carbohydrate supplement (70 g carbohydrate) twice daily. Exercise consisted of alternating resistance training and running 5 times/wk. Plasma concentrations of IGF-I, insulin-like growth factor-binding protein 3, serum bone alkaline phosphatase, and urinary N-telopeptide collagen crosslink (NTx) concentrations were measured at 0, 3, and 6 mo after 24 h without exercise and a 12-h fast.Three-day diet records indicated no difference in energy intake between the groups. Average protein intakes after supplementation began in the protein and carbohydrate groups were 2.2 +/- 0.1 and 1.1 +/- 0.1 g/kg, respectively (P < 0.001). The increase in plasma IGF-I was greater in the protein group than in the carbohydrate group (time x supplement interaction, P = 0.01). There were no significant changes over time or significant differences by supplement in plasma insulin-like growth factor-binding protein 3 (44 and 40 kDa). Serum bone alkaline phosphatase increased significantly over time (P = 0.04) and tended to be higher in the protein group than in the carbohydrate group (P = 0.06). NTx concentrations changed over time (time and time squared; P < 0.01 for both) and were greater in the protein group than in the carbohydrate group (P = 0.04). Men had higher NTx concentrations than did women (74.6 +/- 3.4 and 60.0 +/- 3.8 nmol/mmol creatinine; P = 0.005). Protein supplementation during a strength and conditioning program resulted in changes in IGF-I concentrations.

Ballard TL, Clapper JA, Specker BL, Binkley TL…
Am. J. Clin. Nutr. Jun 2005
PMID: 15941900 | Free Full Text

Beta Blockers May Blunt Exercise Benefits

Abstract

β-Adrenergic receptor blockade blunts postexercise skeletal muscle mitochondrial protein synthesis rates in humans.

β-Adrenergic receptor (AR) signaling is a regulator of skeletal muscle protein synthesis and mitochondrial biogenesis in mice. We hypothesized that β-AR blockade blunts postexercise skeletal muscle mitochondrial protein synthesis rates in adult humans. Six healthy men (mean ± SD: 26 ± 6 yr old, 39.9 ± 4.9 ml·kg(-1)·min(-1) peak O(2) uptake, 26.7 ± 2.0 kg/m(2) body mass index) performed 1 h of stationary cycle ergometer exercise (60% peak O(2) uptake) during 1) β-AR blockade (intravenous propranolol) and 2) administration of saline (control). Skeletal muscle mitochondrial, myofibrillar, and sarcoplasmic protein synthesis rates were assessed using [(2)H(5)]phenylalanine incorporation into skeletal muscle proteins after exercise. The mRNA content of signals for mitochondrial biogenesis was determined using real-time PCR. β-AR blockade decreased mitochondrial (from 0.217 ± 0.076 to 0.135 ± 0.031%/h, P < 0.05), but not myofibrillar or sarcoplasmic, protein synthesis rates. Peroxisome proliferator-activated receptor-γ coactivator-1α mRNA was increased ∼2.5-fold (P < 0.05) at 5 h compared with 1 h postexercise but was not influenced by β-AR blockade. We conclude that decreased β-AR signaling during cycling can blunt the postexercise increase in mitochondrial protein synthesis rates without affecting mRNA content.

Robinson MM, Bell C, Peelor FF, Miller BF
Am. J. Physiol. Regul. Integr. Comp. Physiol. Aug 2011
PMID: 21613574 | Free Full Text

Given that increased muscle tends to increase bone, this is somewhat negative, even though there is some evidence that beta blockers plus exercise is additive for bone.

Beta Blockers or Exercise Improve Bone in Rats

Abstract

Combined effects of exercise and propranolol on bone tissue in ovariectomized rats.

The bone response to physical exercise may be under control of the SNS. Using a running session in rats, we confirmed that exercise improved trabecular and cortical properties. SNS blockade by propranolol did not affect this response on cortical bone but surprisingly inhibited the trabecular response. This suggests that the SNS is involved in the trabecular response to exercise but not in the cortical response.
Animal studies have suggested that bone remodeling is under beta-adrenergic control through the sympathetic nervous system (SNS). However, the SNS contribution to bone response under mechanical loading remains unclear. The purpose of this study was to examine the preventive effect of exercise coupled with propranolol on cancellous and cortical bone compartments in ovariectomized rats.
Six-month-old female Wistar rats were ovariectomized (OVX, n = 44) or sham-operated (n = 24). OVX rats received subcutaneous injections of propranolol 0.1 mg/kg/day or vehicle and were submitted or not submitted to treadmill exercise (13 m/minute, 60 minutes/day, 5 days/week) for 10 weeks. Tibial and femoral BMD was analyzed longitudinally by DXA. At death, the left tibial metaphysis and L(4) vertebrae were removed, and microCT was performed to study trabecular and cortical bone structure. Histomorphometric analysis was performed on the right proximal tibia.
After 10 weeks, BMD and trabecular strength decreased in OVX rats, whereas bone turnover rate and cortical porosity increased compared with the Sham group (p < 0.001). Either propranolol or exercise allowed preservation of bone architecture by increasing trabecular number (+50.35% versus OVX; p < 0.001) and thickness (+16.8% versus OVX; p < 0.001). An additive effect of propranolol and exercise was observed on cortical porosity but not on trabecular microarchitecture or cortical width. Biomechanical properties indicated a higher ultimate force in the OVX-propranolol-exercise group compared with the OVX group (+9.9%; p < 0.05), whereas propranolol and exercise alone did not have any significant effect on bone strength.
Our data confirm a contribution of the SNS to the determinants of bone mass and quality and show a antagonistic effect of exercise and a beta-antagonist on trabecular bone structure.

Bonnet N, Beaupied H, Vico L, Dolleans E…
J. Bone Miner. Res. Apr 2007
PMID: 17243867

Vitamins C + E, or Exercise, Prevent Bone Loss in Women

Abstract

Effect of antioxidants combined to resistance training on BMD in elderly women: a pilot study.

We determined the effect of antioxidants and resistance training on bone mineral density of postmenopausal women. After 6 months, we observed a significant decrease in the lumbar spine BMD of the placebo group while other groups remained stable. Antioxidants may offer protection against bone loss such as resistance training.
The purpose of this pilot study was to determine the effects of antioxidant supplements combined to resistance training on bone mineral density (BMD) in healthy elderly women.
Thirty-four postmenopausal women (66.1 +/- 3.3 years) were randomized in four groups (placebo, n = 7; antioxidants, n = 8; exercise and placebo, n = 11; and exercise and antioxidants, n = 8). The 6-month intervention consisted in antioxidant supplements (600 mg vitamin E and 1,000 mg vitamin C daily) or resistance exercise (3x/week). Femoral neck and lumbar spine BMD (DXA) and dietary intakes (3-day food record) were measured before and after the intervention. A repeated measure ANOVA and non-parametric Mann-Whitney U tests were used.
We observed a significant decrease in the placebo group for lumbar spine BMD (pre, 1.01 +/- 0.17 g/cm(2); post, 1.00 +/- 0.16 g/cm(2); P < 0.05 respectively) while it remained stable in all other groups. No changes were observed for femoral neck BMD.
Antioxidant vitamins may offer some protection against bone loss in the same extent as resistance exercise although combining both does not seem to produce additional effects. Our results suggest to further investigate the impact of antioxidant supplements on the prevention of osteoporosis.

Chuin A, Labonté M, Tessier D, Khalil A…
Osteoporos Int Jul 2009
PMID: 19020919

Review: Milk + Resistance Training

Abstract

Impact of milk consumption and resistance training on body composition of female athletes.

Resistance exercise (RE) preceding the provision of high-quality dairy protein supports muscle anabolism. Milk contains bioactive components, including two high-quality protein fractions, calcium and vitamin D, each of which has been shown modulate body composition (increasing lean mass and decreasing fat mass) under energy balance and hypoenergetic conditions. These dairy nutrients are also essential for skeletal health. Acutely, no study of RE and milk/whey consumption has been undertaken exclusively in female athletes, let alone women, nevertheless, studies with both men and women show increased lean mass accretion following milk/whey compared to soy/placebo. Currently, no longer-term RE studies with milk supplementation have been done in female athletes. However, trials in young recreationally active women demonstrated augmented increases in lean mass and decreases in fat mass with RE and milk or whey protein consumption. The amount of protein consumed post-exercise is also important; two trials using yogurt (5 g protein/6 oz) failed to demonstrate a positive change in body composition compared to placebo. For bone health, RE plus dairy improved bone mineral density at clinically important sites and reduced bone resorption. With energy restriction, in one study, higher dairy plus higher protein resulted in greater fat loss, lean mass gain and improved bone health in overweight women. In another study, milk and calcium supplementation showed no greater benefit. Neither trial exclusively utilized RE. Overall, RE and milk/dairy consumption positively impact body composition in women by promoting losses in fat, gains or maintenance of lean mass and preservation of bone. Future studies in female athletes and under energy restriction with RE alone are warranted.

Josse AR, Phillips SM
Med Sport Sci 2012
PMID: 23075559