Timing of ibuprofen use and bone mineral density adaptations to exercise training

Acetaminophen influences musculoskeletal signaling but not adaptations to endurance exercise training

Acetaminophen (ACE) is a widely used analgesic and antipyretic drug with various applications, from pain relief to fever reduction. Recent studies have reported equivocal effects of habitual ACE intake on exercise performance, muscle growth, and risks to bone health. Thus, this study aimed to assess the impact of a 6-week, low-dose ACE regimen on muscle and bone adaptations in exercising and non-exercising rats. Nine-week-old Wistar rats (n = 40) were randomized to an exercise or control (no exercise) condition with ACE or without (placebo). For the exercise condition, rats ran 5 days per week for 6 weeks at a 5% incline for 2 min at 15 cm/s, 2 min at 20 cm/s, and 26 min at 25 cm/s. A human equivalent dose of ACE was administered (379 mg/kg body weight) in drinking water and adjusted each week based on body weight. Food, water intake, and body weight were measured daily. At the beginning of week 6, animals in the exercise group completed a maximal treadmill test. At the end of week 6, rats were euthanized, and muscle cross-sectional area (CSA), fiber type, and signaling pathways were measured. Additionally, three-point bending and microcomputer tomography were measured in the femur. Follow-up experiments in human primary muscle cells were used to explore supra-physiological effects of ACE. Data were analyzed using a two-way ANOVA for treatment (ACE or placebo) and condition (exercise or non-exercise) for all animal outcomes. Data for cell culture experiments were analyzed via ANOVA. If omnibus significance was found in either ANOVA, a post hoc analysis was completed, and a Tukey's adjustment was used. ACE did not alter body weight, water intake, food intake, or treadmill performance (p > .05). There was a treatment-by-condition effect for Young's Modulus where placebo exercise was significantly lower than placebo control (p < .05). There was no treatment by condition effects for microCT measures, muscle CSA, fiber type, or mRNA expression. Phosphorylated-AMPK was significantly increased with exercise (p < .05) and this was attenuated with ACE treatment. Furthermore, phospho-4EBP1 was depressed in the exercise group compared to the control (p < .05) and increased in the ACE control and ACE exercise group compared to placebo exercise (p < .05). A low dose of ACE did not influence chronic musculoskeletal adaptations in exercising rodents but acutely attenuated AMPK phosphorylation and 4EBP1 dephosphorylation post-exercise.

ACL microtrauma: healing through nutrition, modified sports training, and increased recovery time

PURPOSE

Sports injuries among youth and adolescent athletes are a growing concern, particularly at the knee. Based on our current understanding of microtrauma and anterior cruciate ligament (ACL) healing characteristics, this clinical commentary describes a comprehensive plan to better manage ACL microtrauma and mitigate the likelihood of progression to a non-contact macrotraumatic ACL rupture.

METHODS

Medical literature related to non-contact ACL injuries among youth and adolescent athletes, collagen and ACL extracellular matrix metabolism, ACL microtrauma and sudden failure, and concerns related to current sports training were reviewed and synthesized into a comprehensive intervention plan.

RESULTS

With consideration for biopsychosocial model health factors, proper nutrition and modified sports training with increased recovery time, a comprehensive primary ACL injury prevention plan is described for the purpose of better managing ACL microtrauma, thereby reducing the incidence of non-contact macrotraumatic ACL rupture among youth and adolescent athletes.

CONCLUSION

Preventing non-contact ACL injuries may require greater consideration for reducing accumulated ACL microtrauma. Proper nutrition including glycine-rich collagen peptides, or gelatin-vitamin C supplementation in combination with healthy sleep, and adjusted sports training periodization with increased recovery time may improve ACL extracellular matrix collagen deposition homeostasis, decreasing sudden non-contact ACL rupture incidence likelihood in youth and adolescent athletes. Successful implementation will require compliance from athletes, parents, coaches, the sports medicine healthcare team, and event organizers. Studies are needed to confirm the efficacy of these concepts.

LEVEL OF EVIDENCE

V.

Ibuprofen taken before exercise blunts the IL-6 response in older adults but does not alter bone alkaline phosphatase or c-telopeptide

INTRODUCTION

Non-steroidal anti-inflammatory drugs (NSAIDs) taken before exercise have been shown to impair bone formation. NSAIDs also suppress inflammatory cytokines, such as interleukin-6 (IL-6), that can have pro-resorptive effects. It is unclear how taking NSAIDs timed around exercise influences inflammatory and bone biomarkers following an acute exercise bout in older adults.

PURPOSE

To determine if timing of ibuprofen use relative to a single exercise bout has acute effects on serum IL-6, bone-specific alkaline phosphatase (BAP, marker of bone formation), and c-telopeptide of type I collagen (CTX, marker of bone resorption).

METHODS

As part of a 36-week exercise intervention, participants aged 60 to 75 years were randomized to 3 groups: placebo before and after exercise (PP), ibuprofen before and placebo after exercise (IP), or placebo before and ibuprofen after exercise (PI). Acute responses were studied in a subset of participants (12 PP, 17 IP, 13 PI). Blood was sampled before and immediately, 30 min, and 60 min after exercise for IL-6, BAP, and CTX.

RESULTS

The exercise-induced increase in IL-6 was blunted in response to IP when compared to PI 60-min after exercise (p < 0.001). There were no significant differences in the change in BAP or CTX between groups at any time points CONCLUSION: Ibuprofen taken before exercise dampened the inflammatory response to exercise but had no effects on bone biomarkers in older adults. It may be necessary to monitor changes for a longer time interval after an acute exercise bout to determine whether bone turnover is altered by ibuprofen or other NSAIDs.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00462722; Posted 04/19/2007.

Emerging evidence that adaptive bone formation inhibition by non-steroidal anti-inflammatory drugs increases stress fracture risk

There is mounting evidence suggesting that the commonly used analgesics, non-steroidal anti-inflammatory drugs (NSAIDs), may inhibit new bone formation with physical training and increase risk of stress fractures in physically active populations. Stress fractures are thought to occur when bones are subjected to repetitive mechanical loading, which can lead to a cycle of tissue microdamage, repair, and continued mechanical loading until fracture. Adaptive bone formation, particularly on the periosteal surface of long bones, is a concurrent adaptive response of bone to heightened mechanical loading that can improve the fatigue resistance of the skeletal structure, and therefore may play a critical role in offsetting the risk of stress fracture. Reports from animal studies suggest that NSAID administration may suppress this important adaptive response to mechanical loading. These observations have implications for populations such as endurance athletes and military recruits who are at risk of stress fracture and whose use of NSAIDs is widespread. However, results from human trials evaluating exercise and bone adaptation with NSAID consumption have been less conclusive. In this review, we identify knowledge gaps that must be addressed to further support NSAID-related guidelines intended for at-risk populations and individuals.

Appendicular lean mass is lower in late compared with early perimenopausal women: potential role of FSH

Age-related declines in skeletal muscle mass (i.e., sarcopenia) contribute to physical disability in older women. Although a menopause-related increase in fat mass is well documented, whether menopause influences muscle mass and sarcopenia is unclear. We determined the extent to which skeletal muscle mass differs across the stages of the menopause transition in women and whether these differences are associated with estradiol or other sex hormones. This was a cross-sectional study of 144 healthy women (aged 30-70 yr) classified as premenopausal [n = 30, 38 ± 6 yr (means ± SD)], early (n = 31, 50 ± 3 yr) and late (n = 30, 50 ± 4 yr) perimenopausal, and early (n = 26, 55 ± 3 yr) and late (n = 27, 62 ± 4 yr) postmenopausal. Appendicular lean mass (ALM) adjusted by the square of height in meters (ALM index; ALMi) was assessed by dual-energy X-ray absorptiometry. ALMi was lower (P < 0.05) in late perimenopausal and postmenopausal compared with early perimenopausal, with no significant differences between other groups (premenopausal 6.6 ± 0.6, early perimenopausal 6.8 ± 0.8, late perimenopausal 6.1 ± 0.8, early postmenopausal 6.5 ± 1.1, and late postmenopausal 6.2 ± 0.9 kg/m²). The prevalence of sarcopenia (ALMi ≤ 5.67 kg/m²) was 7%, 3%, 30%, 27%, and 32% in premenopausal, early and late perimenopausal, and early and late postmenopausal groups, respectively. ALMi measured across menopause stages was inversely correlated to follicle-stimulating hormone (FSH; r = -0.28, P = 0.003) but not to estradiol (r = 0.088, P = 0.34). The menopause transition appears to be a vulnerable period for the loss of skeletal muscle mass that may begin during the late perimenopausal transition. Future studies are necessary to investigate the potential effect of FSH on skeletal muscle.NEW & NOTEWORTHY Our data suggest that the late perimenopausal stage may be a vulnerable period for the loss of skeletal muscle, potentially related to elevations in FSH.

Naproxen impairs load-induced bone formation, reduces bone toughness, and diminishes woven bone formation following stress fracture in mice

Debilitating stress fractures are surprisingly common in physically active individuals, including athletes, military recruits, and dancers. These individuals are overrepresented in the 30 million daily users of non-steroidal anti-inflammatory drugs (NSAIDs). We hypothesized that regular use of NSAIDs would predispose habitually loaded bones to stress fracture and delay the repair of these injuries. In this project, we used repetitive axial forelimb compression in mice as a model to test these hypotheses. First, adult mice were subjected to six bouts of forelimb compression over a period of two weeks, with aspirin, naproxen, or vehicle continuously administered through drinking water. Naproxen-treated mice had diminished load-induced bone formation as well as a significant loss in toughness in non-loaded bone, which were not observed in aspirin-treated mice. Furthermore, there were no differences in RANKL/OPG ratio or cortical bone parameters. Picrosirius red staining and second harmonic generation imaging revealed that alterations in bone collagen fibril size and organization were driving the loss of toughness in naproxen-treated mice. Separately, adult mice were subjected to an ulnar stress fracture generated by a single bout of fatigue loading, with NSAIDs provided 24 h before injury. Both aspirin-treated and naproxen-treated mice had normal forelimb use in the week after injury, whereas control mice favored the injured forelimb until day 7. However, woven bone volume was only significantly impaired by naproxen. Both NSAIDs were found to significantly inhibit Ptgs2 and Ngf expression following stress fracture, but only naproxen significantly affected serum PGE2 concentration. Overall, our results suggest that naproxen, but not aspirin, may increase the risk of stress fracture and extend the healing time of these injuries, warranting further clinical evaluation for patients at risk for fatigue injuries.

Influence of Sodium Glucose Cotransporter 2 Inhibition on Physiological Adaptation to Endurance Exercise Training

CONTEXT

The combination of two beneficial antidiabetes interventions, regular exercise and pharmaceuticals, is intuitively appealing. However, metformin, the most commonly prescribed diabetes medication, attenuates the favorable physiological adaptations to exercise; in turn, exercise may impede the action of metformin.

OBJECTIVE

We sought to determine the influence of an alternative diabetes treatment, sodium glucose cotransporter 2 (SGLT2) inhibition, on the response to endurance exercise training.

DESIGN, PARTICIPANTS, AND INTERVENTION

In a randomized, double-blind, repeated measures parallel design, 30 sedentary overweight and obese men and women were assigned to 12 weeks of supervised endurance exercise training, with daily ingestion of either a placebo or SGLT2 inhibitor (dapagliflozin: ≤10 mg/day).

OUTCOME MEASUREMENTS AND RESULTS

Endurance exercise training favorably modified body mass, body composition (dual-energy x-ray absorptiometry), peak oxygen uptake (graded exercise with indirect calorimetry), responses to standardized submaximal exercise (indirect calorimetry, heart rate, and blood lactate), and skeletal muscle (vastus lateralis) citrate synthase activity (main effects of exercise training, all P < 0.05); SGLT2 inhibition did not influence any of these physiological adaptations (exercise training × treatment interaction, all P > 0.05). However, after endurance exercise training, fasting blood glucose was greater with SGLT2 inhibition, and increased insulin sensitivity (oral glucose tolerance test/Matsuda index) was abrogated with SGLT2 inhibition (exercise training × treatment interaction, P < 0.01).

CONCLUSION

The efficacy of combining two beneficial antidiabetes interventions, regular endurance exercise and SGLT2 inhibition, was not supported. SGLT2 inhibition blunted endurance exercise training-induced improvements in insulin sensitivity, independent of effects on aerobic fitness or body composition.

Nonsteroidal Anti-Inflammatory Drug Prescriptions Are Associated With Increased Stress Fracture Diagnosis in the US Army Population

Stress fractures are common in military personnel and endurance athletes, and nonsteroidal anti-inflammatory drug (NSAID) use is widespread in these populations. NSAIDs inhibit prostaglandin synthesis, which blunts the anabolic response of bone to physical activity and could therefore increase risk of stress fracture. The objective of this study was to determine whether prescribed NSAIDs were associated with stress fracture diagnoses among US Army soldiers. We also aimed to establish whether acetaminophen, an analgesic alternative to NSAIDs, was associated with stress fracture risk. A nested case-control study was conducted using data from the Total Army Injury and Health Outcomes Database from 2002 to 2011 (n = 1,260,168). We identified soldiers with a diagnosis of stress fracture (n = 24,146) and selected 4 controls per case matched on length of military service (n = 96,584). We identified NSAID and acetaminophen prescriptions 180 to 30 days before injury (or match date). We also identified soldiers who participated in basic combat training (BCT), a 10-week period of heightened physical activity at the onset of Army service. Among these individuals, we identified 9088 cases and 36,878 matched controls. Conditional logistic regression was used to calculate incident rate ratios (RR) for stress fracture with adjustment for sex. NSAID prescription was associated with a 2.9-fold increase (RR = 2.9, 95% confidence interval [CI] 2.8-2.9) and acetaminophen prescription with a 2.1-fold increase (RR = 2.1, 95% CI 2.0-2.2) in stress fracture risk within the total Army population. The risk was more than 5-fold greater in soldiers prescribed NSAIDs (RR = 5.3, 95% CI 4.9-5.7) and more than 4-fold greater in soldiers prescribed acetaminophen (RR = 4.4, 95% CI 3.9-4.9) during BCT. Our results reveal an association between NSAID and acetaminophen prescriptions and stress fracture risk, particularly during periods of heightened physical activity. Prospective observational studies and randomized controlled trials are needed to support these findings before clinical recommendations can be made. © 2018 American Society for Bone and Mineral Research.

Ibuprofen before Exercise Does Not Prevent Cortical Bone Adaptations to Training

Using a nonsteroidal anti-inflammatory drug (NSAID) before a single bout of mechanical loading can reduce bone formation response. It is unknown whether this translates to an attenuation of bone strength and structural adaptations to exercise training.

PURPOSE

This study aimed to determine whether nonsteroidal anti-inflammatory drug use before exercise prevents increases in bone structure and strength in response to weight-bearing exercise.

METHODS

Adult female Wistar rats (n = 43) were randomized to ibuprofen (IBU) or vehicle (VEH) and exercise (EX) or sedentary (SED) groups in a 2 × 2 (drug and activity) ANCOVA design with body weight as the covariate, and data are reported as mean ± SE. IBU drops (30 mg·kg BW) or VEH (volume equivalent) were administered orally 1 h before the bout of exercise. Treadmill running occurred 5 d·wk for 60 min·d at 20 m·min with a 5° incline for 12 wk. Micro-CT, mechanical testing, and finite element modeling were used to quantify bone characteristics.

RESULTS

Drug-activity interactions were not significant. Exercise increased tibia cortical cross-sectional area (EX = 5.67 ± 0.10, SED = 5.37 ± 0.10 mm, P < 0.01) and structural estimates of bone strength (Imax: EX = 5.16 ± 0.18, SED = 4.70 ± 0.18 mm, P < 0.01; SecModPolar: EX = 4.01 ± 0.11, SED = 3.74 ± 0.10 mm, P < 0.01). EX had increased failure load (EX = 243 ± 9, SED = 202 ± 7 N, P < 0.05) and decreased distortion in response to a 200-N load (von Mises stress at tibia-fibula junction: EX = 48.2 ± 1.3, SED = 51.7 ± 1.2 MPa, P = 0.01). There was no effect of ibuprofen on any measurement tested. Femur results revealed similar patterns.

CONCLUSION

Ibuprofen before exercise did not prevent the skeletal benefits of exercise in female rats. However, exercise that engenders higher bone strains may be required to detect an effect of ibuprofen.

Effects of low-dose ibuprofen supplementation and resistance training on bone and muscle in postmenopausal women: A randomized controlled trial

PURPOSE

To compare the effects of nine months of exercise training and ibuprofen supplementation (given immeditately after exercise sessions) on bone and muscle in postmenopausal women.

METHODS

In a double-blind randomized trial, participants (females: n = 90, mean age 64.8, SD 4.3 years) were assigned (computer generated, double blind) to receive supervised resistance training or stretching 3 days/week, and ibuprofen (400 mg, post-exercise) or placebo (i.e. 4 groups) for 9 months. In this proof-of-concept study the sample size was halved from required 200 identified via 90% power calculation. Baseline and post-intervention testing included: Dual energy x-ray absorptiometry (DXA) for lumbar spine, femoral neck, and total body areal bone mineral density (aBMD); geometry of proximal femur; total body lean tissue and fat mass; predicted 1-repetition maximum muscle strength testing (1RM; biceps curl, hack squat).

RESULTS

Exercise training or ibuprofen supplementation had no effects on aBMD of the lumbar spine, femoral neck, and total body. There was a significant exercise × supplement × time interaction for aBMD of Ward's region of the femoral neck (p = 0.015) with post hoc comparison showing a 6% decrease for stretching with placebo vs. a 3% increase for stretching with ibuprofen (p = 0.017). Resistance training increased biceps curl and hack squat strength vs. stretching (22% vs. 4% and 114% vs. 12%, respectively) (p < 0.01) and decreased percent body fat compared to stretching (2% vs. 0%) (p < 0.05).

CONCLUSIONS

Ibuprofen supplementation provided some benefits to bone when taken independent of exercise training in postmenopausal women. This study provides evidence towards a novel, easily accessible stimulus for enhancing bone health [i.e. ibuprofen].

The role of adaptive bone formation in the etiology of stress fracture

Stress fractures are common injuries with load-bearing activities. Stress fractures have been reported in the scientific literature for over a century; however, the etiology continues to be investigated with important distinctions made between the contributions of the tissue-level processes of bone remodeling and modeling. In response to novel repetitive loading, increased bone remodeling may serve to replace fatigue-damaged bone while at the same time creating temporary porosity. Much attention has been given to the role of remodeling in the etiology of stress fracture; however, the role of bone modeling has received less attention. Modest increases in modeling, via bone formation on the periosteal surface of long bones in response to mechanical loading, greatly increases the fatigue resistance of bone. Thus, enhancing this adaptive bone formation is a promising target for stress fracture prevention, and a focus on adaptive bone formation may reveal novel risk factors for stress fracture.

Understanding Mechanobiology: Physical Therapists as a Force in Mechanotherapy and Musculoskeletal Regenerative Rehabilitation

Achieving functional restoration of diseased or injured tissues is the ultimate goal of both regenerative medicine approaches and physical therapy interventions. Proper integration and healing of the surrogate cells, tissues, or organs introduced using regenerative medicine techniques are often dependent on the co-introduction of therapeutic physical stimuli. Thus, regenerative rehabilitation represents a collaborative approach whereby rehabilitation specialists, basic scientists, physicians, and surgeons work closely to enhance tissue restoration by creating tailored rehabilitation treatments. One of the primary treatment regimens that physical therapists use to promote tissue healing is the introduction of mechanical forces, or mechanotherapies. These mechanotherapies in regenerative rehabilitation activate specific biological responses in musculoskeletal tissues to enhance the integration, healing, and restorative capacity of implanted cells, tissues, or synthetic scaffolds. To become future leaders in the field of regenerative rehabilitation, physical therapists must understand the principles of mechanobiology and how mechanotherapies augment tissue responses. This perspective article provides an overview of mechanotherapy and discusses how mechanical signals are transmitted at the tissue, cellular, and molecular levels. The synergistic effects of physical interventions and pharmacological agents also are discussed. The goals are to highlight the critical importance of mechanical signals on biological tissue healing and to emphasize the need for collaboration within the field of regenerative rehabilitation. As this field continues to emerge, physical therapists are poised to provide a critical contribution by integrating mechanotherapies with regenerative medicine to restore musculoskeletal function.

Effects of pioglitazone or exercise in older adults with mild cognitive impairment and insulin resistance: a pilot study

AIMS

To examine the effects of pioglitazone or endurance exercise training on cognitive function in older adults with mild cognitive impairment (MCI) and insulin resistance.

METHODS

Seventy-eight adults (mean age ± SD: 65 ± 7 years) with central obesity and MCI were randomized to 6 months of endurance exercise, pioglitazone or control.

RESULTS

Sixty-six participants completed the study. Exercise training did not significantly increase peak oxygen uptake compared to control (p = 0.12). Compared to control, insulin resistance improved in the pioglitazone group (p = 0.002) but not in the exercise group (p = 0.25). There was no measureable effect of pioglitazone or exercise on cognitive performance compared to control.

CONCLUSION

In this pilot study, pioglitazone improved insulin resistance but not cognitive performance in older adults with MCI and insulin resistance.

Timing of Ibuprofen Use and Musculoskeletal Adaptations to Exercise Training in Older Adults

Prostaglandins (PGs) increase in bone in response to mechanical loading and stimulate bone formation. Inhibition of cyclooxygenase (COX), the enzyme responsible for PG synthesis, by non-steroidal anti-inflammatory drugs (NSAIDs) impairs the bone formation response to loading in animals when administered before, but not after, loading. The aim was to determine whether the timing of ibuprofen use (400 mg before versus after exercise sessions) is a significant determinant of the adaptive response of BMD to exercise training in older adults. We hypothesized that taking ibuprofen before exercise would attenuate the improvements in total hip and lumbar spine BMD in response to 36 weeks of training when compared with placebo or with ibuprofen use after exercise. Untrained women and men (N = 189) aged 60 to 75 years were randomly assigned to 1 of 3 treatment arms: placebo before and after exercise (PP); ibuprofen before and placebo after exercise (IP); and placebo before and ibuprofen after exercise (PI).

The difference between groups in the change in BMD was not significant when IP was compared with either PP (hip, − 0.5% (− 1.4, 0.4); spine, 0.1% (− 0.9, 1.2)) or PI (hip, 0.3% (− 0.6, 1.2); spine, 0.5% (− 0.5, 1.5)). Ibuprofen use appeared to have more adverse effects on BMD in women than men. The study demonstrated that ibuprofen use did not significantly alter the BMD adaptations to exercise in older adults, but this finding should be interpreted cautiously. It had been expected that the inhibition of bone formation by ibuprofen would be more robust in men than in women, but this did not appear to be the case and may have limited the power to detect the effects of ibuprofen. Further research is needed to understand whether NSAID use counteracts, in part, the beneficial effects of exercise on bone.

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The purpose was to determine whether musculoskeletal adaptations to exercise training in older adults are influenced by NSAID use.

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Ibuprofen use did not significantly alter changes in BMD or fat-free mass, but the study may have been inadequately powered.

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Study attrition was significantly lower in the group that took NSAIDs before exercise suggesting improved tolerance of vigorous bone-loading exercise.

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This was the first randomized, double-blinded placebo- controlled study of ibuprofen effects on BMD from exercise in an older population.

Apparent elastic modulus of ex vivo trabecular bovine bone increases with dynamic loading

Although it is widely known that bone tissue responds to mechanical stimuli, the underlying biological control is still not completely understood. The purpose of this study was to validate required methods necessary to maintain active osteocytes and minimize bone tissue injury in an ex vivo three-dimensional model that could mimic in vivo cellular function. The response of 22 bovine trabecular bone cores to uniaxial compressive load was investigated by using the ZETOS bone loading and bioreactor system while perfused with culture medium for 21 days. Two groups were formed, the "treatment" group (n = 12) was stimulated with a physiological compressive strain (4000 µε) in the form of a "jump" wave, while the "control" group (n = 10) was loaded only during three measurements for apparent elastic modulus on days 3, 10, and 21. At the end of the experiment, apoptosis and active osteocytes were quantified with histological analysis, and bone formation was identified by means of the calcium-binding dye, calcein. It was demonstrated that the treatment group increased the elastic modulus by 61%, whereas the control group increased by 28% (p<0.05). Of the total osteocytes observed at the end of 21 days, 1.7% (±0.3%) stained positive for apoptosis in the loaded group, whereas 2.7% (±0.4%) stained positive in the control group. Apoptosis in the center of the bone cores of both groups at the end of 21 days was similar to that observed in vivo. Therefore, the three-dimensional model used in this research permitted the investigation of physiological responses to mechanical loads on morphology adaptation of trabecular bone in a controlled defined load and chemical environment.

Ingestion of low-dose ibuprofen following resistance exercise in postmenopausal women

BACKGROUND

Postmenopausal women typically experience accelerated muscle loss which has a negative effect on strength. The maximum daily recommended dosage of ibuprofen (1,200 mg) following resistance exercise has been shown to increase muscle hypertrophy and strength in older adults. This study aimed to determine the effects of low-dose ibuprofen (400 mg) immediately following resistance exercise sessions on muscle mass and strength in postmenopausal women.

METHODS

Participants were randomized to ingest ibuprofen (IBU: n = 15, 57.8 ± 5.1 years, 75.9 ± 9.0 kg, 165.9 ± 6.2 cm, BMI = 28 ± 4 kg/m(2)) or placebo (PLA: n = 13, 56.5 ± 4.4 years, 73.0 ± 10.4 kg, 163.1 ± 5.9 cm, BMI = 26 ± 9 kg/m(2)) immediately following resistance exercise (11 whole-body exercises), which was performed 3 days/week, on nonconsecutive days, for 9 weeks. Prior to and following training, measures were taken for lean tissue mass (dual-energy X-ray absorptiometry), muscle size of the elbow and knee flexors and extensors and ankle dorsiflexors and plantar flexors (ultrasound), and strength (one-repetition maximum leg press and chest press).

RESULTS

Over the 9 weeks of training, there were significant changes (p < 0.05) in lean tissue mass (IBU, -1.1 ± 1.0 kg; PLA, -0.7 ± 1.4 kg), muscle size of the knee extensors (IBU, 0.3 ± 0.6 cm; PLA, 0.2 ± 0.7 cm), ankle dorsiflexors (IBU, 0.5 ± 0.8 cm; PLA, 0.1 ± 0.5 cm), and ankle plantar flexors (IBU, 0.3 ± 0.9 cm; PLA, 0.5 ± 0.9 cm), leg press strength (IBU, 20.6 ± 18.0 kg; PLA, 20.0 ± 20.0 kg), and chest press strength (IBU, 5.1 ± 9.5 kg; PLA, 8.1 ± 7.6 kg), with no differences between groups.

CONCLUSION

Low-dose ibuprofen following resistance exercise has no greater effect on muscle mass or strength over exercise alone in postmenopausal women.

The cyclooxygenase-2 selective inhibitor NS-398 does not influence trabecular or cortical bone gain resulting from repeated mechanical loading in female mice

A single injection of the cyclooxygenase-2 (COX-2) selective inhibitor NS-398 reduces bone's osteogenic response to a single period of mechanical loading in female rats, while women taking COX-2 selective inhibitors do not have lower bone mass. We show that daily NS-398 injection does not influence bone gain from repeated loading in female mice.

INTRODUCTION

Prostaglandins are mediators of bone cells' early response to mechanical stimulation. COX-2 expression is up-regulated by exposure of these cells to mechanical strain or fluid flow, and the osteogenic response to a single loading period is reduced by COX-2 inhibition. This study determined, in female mice in vivo, the effect of longer term COX-2 inhibition on adaptive (re)modelling of cortical and trabecular bone in response to repeated loading.

METHODS

Nineteen-week-old female C57BL/6 mice were injected with vehicle or NS-398 (5 mg/kg/day) 5 days a week for 2 weeks. On three alternate days each week, the right tibiae/fibulae were axially loaded [40 cycles (7 min)/day] three hours after injection. Left limbs acted as internal controls. Changes in three-dimensional bone architecture were analysed by high-resolution micro-computed tomography.

RESULTS

In control limbs NS-398 was associated with reduced trabecular number but had no influence on cortical bone. In loaded limbs trabecular thickness and cortical periosteally enclosed volume increased. NS-398 showed no effect on this response.

CONCLUSION

Pharmacological inhibition of COX-2 by NS-398 does not affect trabecular or cortical bone's response to repeated mechanical loading in female mice and thus would not be expected to impair the functional adaptation of bone to physical activity in women.

N-acetyl-4-aminophenol and musculoskeletal adaptations to resistance exercise training

N-acetyl-4-aminophenol (ACET) may impair musculoskeletal adaptations to progressive resistance exercise training (PRT) by inhibiting exercise-induced muscle protein synthesis and bone formation. To test the hypothesis that ACET would diminish training-induced increases in fat-free mass (FFM) and osteogenesis, untrained men (n = 26) aged ≥50 years participated in 16 weeks of high-intensity PRT and bone-loading exercises and were randomly assigned to take ACET (1,000 mg/day) or placebo (PLAC) 2 h before each exercise session. Total body FFM was measured by DXA at baseline and week 16. Serum bone-specific alkaline phosphatase (BAP) and C-terminal crosslinks of type-I collagen (CTX) were measured at baseline and week 16. Vastus lateralis muscle biopsies were performed at baseline and weeks 3 and 16 for prostanoid, anabolic, and catabolic gene expression by RT-PCR. In exercise-compliant men (ACET, n = 10; PLAC, n = 7), the increase in FFM was not different between groups (p = 0.91). The changes in serum BAP and CTX were not different between groups (p > 0.7). There were no significant changes in any of the target genes at week 3. After 16 weeks of PRT, the mRNA expressions of the anabolic marker p70S6K (p = 0.003) and catabolic marker muscle-atrophy F-box (MAFbx) (p = 0.03) were significantly reduced as compared to baseline in ACET. The mRNA expression of the prostanoids were unchanged (all p ≥ 0.40) in both groups. The administration of ACET (1,000 mg) prior to each exercise session did not impair PRT-induced increases in FFM or significantly alter bone formation markers in middle aged and older men.

Pharmacologic treatment of knee osteoarthritis in athletic women

There is a greater incidence of anterior cruciate ligament tears due to noncontact sports injuries in women compared with men. Anterior cruciate ligament tears are associated with accelerated development of knee osteoarthritis (OA), which is also more prevalent in women than in men. This article considers therapeutic modalities that are best suited for athletic women with knee OA. Clinical data on the safety and efficacy of pharmacotherapies for knee OA, including acetaminophen, oral nonsteroidal anti-inflammatory drugs (NSAIDs), and topical NSAIDs, are discussed, with attention paid to special considerations for women who participate in athletic activity. Adverse events associated with the use of acetaminophen and oral NSAIDs place potential limits on the dose and duration of therapy and may be of greater concern in female athletes than in other patient groups. Topical NSAIDs, which effect relief through the same mechanism of action as oral NSAIDs, produce dramatically lower systemic NSAID exposure compared with oral NSAIDs and are associated with a lower incidence of systemic adverse events. These findings, along with additional future studies, may have particular relevance to the choice of the most effective treatment options for athletic women with OA of the knee.

Role of endocrine and paracrine factors in the adaptation of bone to mechanical loading

There appears to be no unique mechanically sensitive pathway by which changes in bone loading regulate bone mass and architecture to ensure adequate structural strength. Rather, strain-derived changes in bone cells activate a number of nonspecific strain-sensitive pathways (including calcium fluxes, prostanoids, nitric oxide, extracellular signal-regulated kinase, and sclerostin), the activities of which are modified by a number of factors (including estrogen receptors) for which this contribution is subsidiary to other purposes. The strain-sensitive pathways modified by these factors interact with a number of other pathways, some of which appear to have specific osteoregulatory potential (eg, the parathyroid hormone pathway), whereas others such as the Wnt pathway appear to be associated primarily with the response mechanisms of proliferation, differentiation, and apoptosis. The outcome of these multiple interactions are stimuli for local bone formation, resorption, or maintenance of the status quo, to maintain existing bone architecture or adapt it to a new mechanical regimen.