Estimating Hemodynamic Responses to the Wingate Test Using Thoracic Impedance

Techniques including direct Fick and Doppler echocardiography are frequently used to assess hemodynamic responses to exercise. Thoracic impedance has been shown to be a noninvasive alternative to these methods for assessing these responses during graded exercise to exhaustion, yet its feasibility during supramaximal bouts of exercise is relatively unknown. We used thoracic impedance to estimate stroke volume (SV) and cardiac output (CO) during the Wingate test (WAnT) and compared these values to those from graded exercise testing (GXT). Active men (n = 9) and women (n = 7) (mean age = 24.8 ± 5.9 yr) completed two Wingate tests and two graded exercise tests on a cycle ergometer. During exercise, heart rate (HR), SV, and CO were continuously estimated using thoracic impedance. Repeated measures analysis of variance was used to identify potential differences in hemodynamic responses across protocols. Results: Maximal SV (138.6 ± 37.4 mL vs. 135.6 ± 26.9 mL) and CO (24.5 ± 6.1 L·min^-1 vs. 23.7 ± 5.1 L·min^-1) were similar (p > 0.05) between repeated Wingate tests. Mean maximal HR was higher (p < 0.01) for GXT (185 ± 7 b·min^-1) versus WAnT (177 ± 11 b·min^-1), and mean SV was higher in response to WAnT (137.1 ± 32.1 mL) versus GXT (123.0 ± 32.0 mL), leading to similar maximal cardiac output between WAnT and GXT (23.9 ± 5.6 L·min^-1 vs. 22.5 ± 6.0 L·min^-1). Our data show no difference in hemodynamic responses in response to repeated administrations of the Wingate test. In addition, the Wingate test elicits similar cardiac output compared to progressive cycling to VO₂max.

Key points

• Measurement of cardiac output (CO), the rate of oxygen transport delivered by the heart to skeletal muscle, is not widely-employed in Exercise Physiology due to the level of difficulty and invasiveness characteristic of most techniques used to measure this variable.
• Nevertheless, thoracic impedance has been shown to provide a noninvasive and simpler approach to continuously measure CO at rest and during exercise.
• Results show that measurements of CO are not different and highly reliable in response to repeated administrations of the Wingate test.
• Despite vastly different intensities and durations, maximal CO was similar between the Wingate test and graded exercise to VO₂max.

Key words: Stroke volume, cardiac output, cycle ergometer, maximal oxygen uptake, supramaximal exercise     

The Effects of Bicycle Frame Geometry on Muscle Activation and Power During a Wingate Anaerobic Test

The purpose of this study was to compare the effects of bicycle seat tube angles (STA) of (72° and 82°) on power production and EMG of the vastus laeralis (VL), vastus medialis (VM), semimembranous (SM), biceps femoris (BF) during a Wingate test (WAT). Twelve experienced cyclists performed a WAT at each STA. Repeated measures ANOVA was used to identify differences in muscular activation by STA. EMG variables were normalized to isometric maximum voluntary contraction (MVC). Paired t-tests were used to test the effects of STA on: peak power, average power, minimum power and percent power drop. Results indicated BF activation was significantly lower at STA 82° (482.9 ± 166.6 %MVC·s) compared to STA 72° (712.6 ± 265.6 %MVC·s). There were no differences in the power variables between STAs. The primary finding was that increasing the STA from 72° to 82° enabled triathletes’ to maintain power production, while significantly reducing the muscular activation of the biceps femoris muscle.

Key Points

• Road cyclists claim that bicycle seat tube angles between 72° and 76° are most effective for optimal performance in racing.
• Triathletes typically use seat tube angles greater than 76°. It is thought that a seat tube angle greater than 76° facilitates a smoother bike to run transition in the triathlon.
• Increasing the seat tube angle from 72 to 82 enabled triathletes’ to maintain power production, while significantly reducing the muscular activation of the biceps femoris muscle.
• Reduced hamstring muscular activation in the triathlon frame (82 seat tube angle) may serve to reduce hamstring tightness following the bike phase of the triathlon, allowing the runner to use a longer stride length.

Key words: Cycling, anaerobic power, triathlon, efficiency, EMG     

Reliability of arm Wingate Anaerobic Testing in persons with complete paraplegia

BACKGROUND: Accurate, reliable assessment of upper extremity muscular power in persons with paraplegia caused by spinal cord injury (SCI) would provide an objective indication of their ability to generate the forces necessary for the performance of daily activities. Wingate Anaerobic Testing (WAnT) consists of a 30-second sprint test on a cycle ergometer and has been used widely in both athletic and research settings. PURPOSE: To examine test-retest reliability of arm WAnT performance in persons with complete SCI and paraplegia. METHODS: Forty-three participants with thoracic-level paraplegia (T2 through T12) performed 2 trials of arm WAnT with 2 to 7 days between each trial. Testing was performed using a Monarch 834E ergometer with participants seated in their wheelchairs. Participants were directed to crank at maximal pace for 30 seconds against a resistance load equivalent to 3.5% of their body mass. The SMI OptoSensor 2000 system was used to determine values of peak power (P(peak)), mean power (P(mean)), minimum power, and rate of fatigue, which were compared between trials using 1-way analysis of variance for repeated measures. Coefficients of determination (r2) were calculated between trials for P(peak) and P(mean). RESULTS: No significant difference was found between trials for any of the power output variables. Regression analysis indicated that P(peak) and P(mean) were closely associated between the 2 trials (r2 = 0.92 and 0.94, respectively). CONCLUSION: Arm WAnT is a reliable measurement tool for the assessment of upper extremity muscular power in persons with complete paraplegia.     

老年男性的睾酮替代疗法

男性正常衰老过程伴随血清睾酮水平下降 ,但是尚不清楚它是否将导致许多男性的睾酮缺乏症。过去 10年中 ,越来越多的研究兴趣转向确认对那些睾酮缺乏的老年男性采用睾酮替代疗法 (TRT)是否有助于阻止或逆转衰老的某些方面。TRT有益效应相关的主要雄性激素靶器官包括 :骨、肌肉、脂肪组织、心血管系统和脑。与此同时 ,TRT对靶器官 (如前列腺 )的潜在不良反应仍需评估。本文的目的是总结有关老年男性TRT问题的最新认识。     

Synergistic effects of FGF-2 with insulin or IGF-I on the proliferation of human auricular chondrocytes

Chondrocyte preparation with the safety and efficiency is the first step in cartilage regenerative medicine. To prepare a chondrocyte proliferation medium that does not contain fetal bovine serum (FBS) and that provides more than a 1000-fold increase in cell numbers within approximately 1 month, we attempted to use the medium containing 5% human serum (HS), but it exerted no more than twofold increase in 2 weeks. To compensate for the limited proliferation ability in HS, we investigated the combinational effects of 12 factors [i.e., fibroblast growth factor (FGF)-2, insulin-like growth factor (IGF)-I, insulin, bone morphogenetic protein-2, parathyroid hormone, growth hormone, dexamethasone, 1alpha25-dihydroxy vitamin D3, L-3,3',5'-triodothyronine, interleukine-1 receptor antagonist, 17beta-estradiol, and testosterone] on the proliferation of human auricular chondrocytes by analysis of variance in fractional factorial design. As a result, FGF-2, dexamethasone, insulin, and IGF-I possessed promotional effects on proliferation, while the combination of FGF-2 with insulin or IGF-I synergistically enhanced the proliferation. Actually, the chondrocytes increased 7.5-fold in number in 2 weeks in a medium containing 5% HS with 10 ng/ml FGF-2, while the cell number synergistically gained a 10-12-fold increase with 5 microg/ml insulin or 100 ng/ml IGF-I in the same period. The proliferation effects were more enhanced at a concentration of 100 ng/ml for FGF-2, and especially for the combination of 100 ng/ml FGF-2 and 5 microg/ml insulin (approximately 16-fold within 2 weeks). In the long-term culture with repeated passaging, this combination provided more than 10,000-fold within 8 weeks (i.e., passage 4). Thus, we concluded that such a combination of FGF-2 with insulin or IGF-I may be useful for promotion of auricular chondrocyte proliferation in a clinical application for cartilage regeneration.     

Increased Cortical Porosity in Older Men With Fracture

Cortical porosity increases with age and affects bone strength, but its association with fracture in older men is unknown. The aim of this study was to investigate whether cortical porosity is associated with prevalent fractures in older men. A subsample of 456 men aged 80.2 ± 3.5 (mean ± SD) years, with available high‐resolution peripheral quantitative computed tomography measurements at the tibia from the 5‐year follow‐up exam, was drawn from the prospective MrOS Gothenburg study. Dual‐energy X‐ray absorptiometry was used to measure areal bone mineral density (aBMD). Data on physical activity, calcium intake, medications, diseases, and smoking were collected on questionnaires at the follow‐up exam. Of 87 men (19.1%) with fracture at or after age 50 years (all fracture group), 52 (11.4%) had had a self‐reported fracture before the baseline exam and 35 (7.7%) had had an X‐ray–verified fracture between baseline and follow‐up. Men in the all‐fracture group and in the X‐ray–verified group had 15.8% (13.2% ± 4.9% versus 11.4% ± 3.8%; p < 0.001) and 21.6% (14.1% ± 5.2% versus 11.6% ± 3.9%; p < 0.01) higher cortical porosity, respectively, than men in the nonfracture group. The independent associations between bone microstructure parameters and fracture were tested using multivariate logistic regression with age, height, weight, calcium intake, smoking, physical activity, medications, and diseases as covariates. Cortical porosity was independently associated with any fracture (reported or X‐ray–verified; OR per SD increase 1.49; 95% confidence interval (CI), 1.17 to 1.90) and with any X‐ray–verified fracture alone (OR 1.73; 95% CI, 1.23 to 2.42). Including aBMD (spine or hip, respectively) in the multivariate logistic regression above revealed that cortical porosity was associated with any fracture (OR 1.54; 95% CI, 1.17 to 2.01) and with X‐ray–verified fracture alone (OR 1.49; 95% CI, 1.00 to 2.22). Cortical porosity was associated with prevalence of fracture even after adjustment for aBMD. © © 2015 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research (ASBMR).     

Determinants of Bone Mineral Density in Older Men

Although osteoporosis in men is increasingly recognized as an important health issue and bone mass appears to be a major determinant of fracture, there remain few data concerning the determinants of bone mass in men. To determine the correlates of bone density in men, we studied a large group of older subjects recruited from three rural communities in the northwestern United States. Three hundred and fifty-five men over the age of 60 years (mean 71.5 ± 7.4 years) without known disorders of mineral metabolism were recruited by community advertising. Bone mineral density was measured at the lumbar spine, proximal femur and radius by dual-energy X-ray absorptiometry, and factors potentially related to skeletal status were assessed by direct measurements or questionnaire. In univariate analyses weight (positively) and age (negatively) were associated with bone density. After adjustment for these two factors, alcohol intake, osteoarthritis and thiazide use were associated with higher bone density, while previous fractures, gastrectomy, peptic ulcer disease, rheumatoid arthritis, glucocorticoid use, hypertension, previous hyperthyroidism, height loss since age 20 years, chronic lung disease and smoking were related to lower density. In multivariate models, only weight and a history of cancer were related to higher bone mass, and age, previous fracture, rheumatoid arthritis, gastrectomy and hypertension were associated with lower density. These data contribute to the emerging field of osteoporosis in men, and may help in the clinical identification of men at higher risk of osteopenia. Received: 27 September 1999 / Accepted: 20 March 2000     

Time-of-Day Effects on EMG Parameters During the Wingate Test in Boys

In boys, muscle power and strength fluctuate with time-of-day with morning nadirs and afternoon maximum values. However, the exact underlying mechanisms of this daily variation are not studied yet. Thus, the purpose of this study was to examine the time-of-day effects on electromyographic (EMG) parameters changes during a Wingate test in boys. Twenty-two boys performed a 30-s Wingate test (measurement of muscle power and fatigue) at 07:00 and 17:00-h on separate days. Surface EMG activity was recorded in the Vastus lateralis, rectus femoris and vastus medialis muscles throughout the test and analyzed over a 5-s span. The root-mean-square (RMS) and mean-power-frequency (MPF) were calculated. Neuromuscular efficiency (NME) was estimated from the ratio of power to RMS. Muscle power (8.22 ± 0.92 vs. 8.75 ± 0.99 W·kg^-1 for peak power and 6.96 ± 0. 72 vs. 7.31 ± 0.77 W·kg^-1 for mean power, p < 0.001) and fatigue (30.27 ± 7.98 vs. 34.5 ± 10. 15 %, p < 0.05) during the Wingate test increased significantly from morning to evening. Likewise, MPF (102.14 ± 18.15 vs. 92.38 ± 12.39 Hz during the first 5-s, p < 0.001) and NME (4.78 ± 1.7 vs. 3.88 ± 0.79 W·mV^-1 during the first 5-s, p < 0.001) were higher in the evening than the morning; but no significant time-of-day effect was noticed for RMS. Taken together, these results suggest that peripheral mechanisms are more likely the cause of the child’s diurnal variations of muscle power and fatigue during the Wingate test.

Key points

• In boys, performances during the Wingate test fluctuate with the time-of-day.
• MPF and NME are higher in the evening during the Wingate cycling test.
• RMS is unaffected by the time-of-day.
• The evening improvement in muscle power and fatigue is due to an enhancement of the muscle contractile properties.

Key words: Dkwdurnal variation, muscle power, muscle fatigue, electromyography, pre-pubertal     

Characteristics Associated with Bone Mineral Density Responses to Alendronate in Men

Some patients experience reduced bone mineral density (BMD) despite bisphosphonate therapy. We performed a retrospective chart review study to detect factors associated with decreased BMD in men prescribed alendronate. Two investigators reviewed eligible medical records and used a standardized form to record potential characteristics predicting men’s response to alendronate. We analyzed patient characteristics associated with annualized change in hip and spine BMD (D-BMD). Among 115 eligible men, 19 (17 %) experienced significantly decreased BMD at the hip or spine, defined as a change exceeding precision error. Eleven men (10 %) fractured during therapy. Spine D-BMD was positively associated with adherence to alendronate (R = 0.23, p = 0.02) and inversely associated with baseline body weight (R = ?0.21, p = 0.03). Hip D-BMD was positively associated with annualized weight change (R = 0.19, p = 0.0498) and negatively associated with patient age and number of concomitant medications (R = ?0.21, p = 0.03; R = ?0.20, p = 0.03, respectively). In stepwise linear models, spine D-BMD was associated positively with alendronate adherence and multivitamin use and negatively with baseline body weight. Hip D-BMD was negatively associated with age. Fracture during treatment was associated with fracture prior to therapy (p = 0.03). In this small study of men prescribed alendronate, BMD response showed a positive association with adherence to therapy, weight gain, and use of a multivitamin. By contrast, older age, higher baseline body weight, and higher number of medications were each associated with a decrease in BMD. Larger studies are needed to confirm and extend these findings.     

Physical Performance and Risk of Hip Fractures in Older Men

The aim of these analyses was to describe the association between physical performance and risk of hip fractures in older men. Performance on five physical function exams (leg power, grip strength, usual walking pace, narrow walk balance test, and five repeated chair stands) was assessed in 5902 men ≥65 yr of age. Performance (time to complete or strength) was analyzed as quartiles, with an additional category for unable to complete the measure, in proportional hazards models. Follow‐up averaged 5.3 yr; 77 incident hip fractures were confirmed by physician review of radiology reports. Poor physical performance was associated with an increased risk of hip fracture. In particular, repeated chair stand performance was strongly related to hip fracture risk. Men unable to complete this exam were much more likely to experience a hip fracture than men in the fastest quartile of this test (multivariate hazard ratio [MHR]: 8.15; 95% CI: 2.65, 25.03). Men with the worst performance (weakest/slowest quartile or unable) on at least three exams had an increased risk of hip fracture compared with men with higher functioning (MHR: 3.14, 95% CI: 1.46, 6.73). Nearly two thirds of the hip fractures (N = 49, 64%) occurred in men with poor performance on at least three exams. Poor physical function is independently associated with an increased risk of hip fracture in older men. The repeated chair stands exam should be considered in clinical settings for evaluation of hip fracture risk. Concurrent poor performance on multiple physical function exams is associated with an increased risk of hip fractures.     

Physical Performance and Radiographic and Clinical Vertebral Fractures in Older Men

In men, the association between poor physical performance and likelihood of incident vertebral fractures is unknown. Using data from the MrOS study (N = 5958), we describe the association between baseline physical performance (walking speed, grip strength, leg power, repeat chair stands, narrow walk [dynamic balance]) and incidence of radiographic and clinical vertebral fractures. At baseline and follow‐up an average of 4.6 years later, radiographic vertebral fractures were assessed using semiquantitative (SQ) scoring on lateral thoracic and lumbar radiographs. Logistic regression modeled the association between physical performance and incident radiographic vertebral fractures (change in SQ grade ≥1 from baseline to follow‐up). Every 4 months after baseline, participants self‐reported fractures; clinical vertebral fractures were confirmed by centralized radiologist review of the baseline study radiograph and community‐acquired spine images. Proportional hazards regression modeled the association between physical performance with incident clinical vertebral fractures. Multivariate models were adjusted for age, bone mineral density (BMD, by dual‐energy X‐ray absorptiometry [DXA]), clinical center, race, smoking, height, weight, history of falls, activity level, and comorbid medical conditions; physical performance was analyzed as quartiles. Of 4332 men with baseline and repeat radiographs, 192 (4.4%) had an incident radiographic vertebral fracture. With the exception of walking speed, poorer performance on repeat chair stands, leg power, narrow walk, and grip strength were each associated in a graded manner with an increased risk of incident radiographic vertebral fracture (p for trend across quartiles <0.001). In addition, men with performance in the worst quartile on three or more exams had an increased risk of radiographic fracture (odds ratio [OR] = 1.81, 95% confidence interval [CI] 1.33–2.45) compared with men with better performance on all exams. Clinical vertebral fracture (n =149 of 5813, 2.6%) was not consistently associated with physical performance. We conclude that poorer physical performance is associated with an increased risk of incident radiographic (but not clinical) vertebral fracture in older men. © 2014 American Society for Bone and Mineral Research.     

Familiarization Effects of an Elliptical All-out Test and the Wingate Test Based on Mechanical Power Indices

The Wingate all-out test (WAT) is commonly used to estimate anaerobic capabilities of athletes by using an upper or lower body cycle ergometer, however, a new test modality called elliptical all-out test (EAT) which measures activated whole-body locomotor tasks has recently been proposed. The purpose of this study was to evaluate the familiarization effects of a 30-s EAT versus WAT. Twenty male trained athletes performed pre-familiarization (Trial- I), post-familiarization (Trial-II) and retest of Trial-II (Trial-III) sessions on both cycle ergometer and elliptical trainer. Peak power (PP), average power (AP), power drop (PD) and fatigue index ratio (FI%) were analyzed using student''s t-test for paired samples and correlated by intra-class correlation coefficients (ICC). Moreover, an error detection procedure was administered using data attained from illogical interrelations among 5-s segments of 30-s tests. The main results showed that there were significant familiarization effects in all mechanical power outputs obtained from Trial-I and Trial-II in both EAT (ICC = 0.49-0.55) and WAT (ICC = 0.50-0.57) performances (p ≤ 0.01). Significant segmental disorders were detected in power production during Trial-I of EAT, however, none existed in any of test trails in the WAT (p ≤ 0.001). After familiarization sessions, reliability coefficients between Trial-II and Trial-III showed moderate to strong-level agreements for both EAT (ICC = 0.74-0.91) and the WAT (ICC=0.76-0.93). Our results suggested that prior to the performance tests, combination of a well designed familiarization session with one full all-out test administration is necessary to estimate the least moderately reliable and accurate test indices for both WAT and EAT.

Key Points

• A well designed familiarization session, and then, one additional all-out test administration, several days prior to main test, is suggested to estimate more accurate and reliable retest correlations for both cycling and elliptical all-out test modalities.
• Because of greater muscle recruitment and different movement pattern, familiarization seems more effective for a 30-s all-out test performed on an elliptical trainer compared to a cycle ergometer.

Key words: Adaptation, anaerobic, coordination, practice, reliability, Wingate     

Glycemic Control and Insulin Treatment Alter Fracture Risk in Older Men With Type 2 Diabetes Mellitus

Diabetes mellitus among older men has been associated with increased bone mineral density but paradoxically increased fracture risk. Given the interactions among medication treatment, glycemic control, and diabetes-associated comorbidities, the relative effects of each factor remains unclear. This retrospective study includes 652,901 male veterans aged ≥65 years with diabetes and baseline hemoglobin A1c (HbA1c) value. All subjects received primary care in the Veterans Health Administration (VHA) from 2000 to 2010. Administrative data included ICD9 diagnoses and pharmacy records and was linked to Medicare fee-for-service data. Hazard ratios (HR) for any clinical fracture and hip fracture were calculated using competing risk hazards models, adjusted for fracture risk factors including age, race/ethnicity, body mass index (BMI), alcohol and tobacco use, rheumatoid arthritis, corticosteroid use, as well as diabetes-related comorbidities including cardiovascular disease, chronic kidney disease, and peripheral neuropathy. HbA1c <6.5% was associated with a higher risk of any clinical fracture (HR = 1.08, 95% confidence interval [CI] 1.06–1.11) compared with the reference HbA1c of 7.5% to 8.5%. Fracture risk was not increased among those with A1c ≥8.5%, nor among those with A1c 6.5% to 7.5%. Use of insulin was independently associated with greater risk of fracture (HR = 1.10, 95% CI 1.07–1.12). There was a significant interaction between insulin use and HbA1c level, (p < 0.001), such that those using insulin with HbA1c <6.5% had HR = 1.23 and those with HbA1c 6.5% to 7.5% had HR = 1.15. Metformin use was associated with decreased fracture risk (HR = 0.88, 95% CI 0.87–0.90). We conclude that among older men with diabetes, those with HbA1c lower than 6.5% are at increased risk for any clinical and hip fracture. Insulin use is associated with higher fracture risk, especially among those with tight glycemic control. Our findings demonstrate the importance of the treatment regimen and avoiding hypoglycemia for fracture prevention in older men with diabetes. © 2019 American Society for Bone and Mineral Research.     

Femoroacetabular Impingement: Prevalent and Often Asymptomatic in Older Men: The Osteoporotic Fractures in Men Study

Background

The epidemiology of femoroacetabular impingement (FAI) is important but incompletely understood, because most reports arise from symptomatic populations. Investigating the prevalence of FAI in a community-based cohort could help us better understand its epidemiology and in particular the degree to which it might or might not be associated with hip pain.

Questions/purposes

The purposes of this study were (1) to evaluate the proportion of older (≥ 65 years of age) men with morphologic abnormalities consistent with FAI; and (2) to assess the association of the morphologic abnormalities with prevalent radiographic hip osteoarthritis (OA) and hip pain.

Methods

Anteroposterior radiographs were obtained in 4140 subjects (mean age ± SD, 77 ± 5 years) from the Osteoporotic Fractures in Men study. We assessed each hip for cam, pincer, and mixed FAI types using validated radiographic definitions. Both intra- and interobserver reproducibility were > 0.9. Radiographic hip OA was assessed by an expert reader (intraobserver reproducibility, 0.7–0.8) using validated methods, and summary grades of 2 or greater (on a scale from 0 to 4) were used to define radiographic hip OA. Covariates including hip pain in the last 30 days were collected by questionnaires that were answered by all patients included in this report. Logistic regressions with generalized estimating equations were performed to evaluate the association of radiographic features of FAI and arthrosis.

Results

Pincer, cam, or mixed types of radiographic FAI had a prevalence of 57% (1748 of 3053), 29% (886 of 3053), and 14% (419 of 3053), respectively, in this group of older men. Both pincer and mixed types of FAI were associated with arthrosis but not with hip pain (odds ratio [OR], 1.63; 95% confidence interval [CI], 1.25–2.13; p < 0.001 for pincer and OR, 2.49; 95% CI, 1.65–3.76; p < 0.001 for mixed type). Patients with hips characterized by cam-type FAI had slightly reduced hip pain without the presence of arthrosis compared with hips without FAI (OR, 0.82; 95% CI, 0.68–0.99; p = 0.037). A center-edge angle > 39° and a caput-collum-diaphyseal angle < 125° were associated with arthrosis (OR, 1.53; 95% CI, 1.22–1.94; p < 0.001 and OR, 2.09; 95% CI, 1.24–3.51; p = 0.006, respectively), but not with hip pain (OR, 0.89; 95% CI, 0.77–1.03; p < 0.108 and OR, 0.99; 95% CI, 0.67–1.45; p = 0.945, respectively). An impingement angle < 70° was associated with less hip pain compared with hips with an impingement angle ≥ 70° (OR, 0.76; 95% CI, 0.61–0.95; p = 0.015).

Conclusions

FAI is common in older men and represents more of an anatomic variant rather than a symptomatic disease. This finding should raise questions on how age, activities, and this anatomic variant each contribute to result in symptomatic disease.

Level of Evidence

Level III, prognostic study.     

Physiological Responses to 90 s All Out Isokinetic Sprint Cycling in Boys and Men

The purpose of this study was to compare the VO₂ kinetic and mechanical power responses of boys and men to all out 90 s sprint cycle exercise. Eight boys (14.6 ± 0.3 y) and eight men (33.8 ± 6.5 y) volunteered to participate and completed a ramp test (to determine VO_2peak and ventilatory threshold, VT) and then on subsequent days, two 90 s all out cycle sprints on an isokinetic cycle ergometer. During each test, breath-by-breath pulmonary gas exchange and power output were measured. Parameters from the power output profiles were derived from the average response of the two tests including peak power (PP, highest power output in 1 s), end power (EP_60-90, power over the last 30 s), and mean power over the 90 s (MP₉₀). Independent pairwise and dependent t-tests were used to compare the data from tests between adults and boys subject groups. Significant differences between adults and boys were found for absolute PP (881.4 ± 60.7 vs 533.6 ± 50.7 W), EP_60-90 (288.6 ± 25.7 vs 134.3 ± 17.6 W) and MP₉₀ (434.5 ± 27.4 vs 238.4 ± 17.3 W, p =0.001) respectively. Relative to body mass significant differences between adults and boys were found for EP_60-90, MP₉₀ and total work (p < 0.002). The boys attained 90 s VO₂ values that were closer to VO_2peak than their adult counterparts (93.3 ± 2.6 vs 84.9 ± 2.3 %, p = 0.03). They also demonstrated faster VO₂ kinetics (10.8 ± 1.5 vs 17.6 ± 1.0 s, p < 0.01). In conclusion, during all out 90 s cycle sprinting boys were able to attain VO₂ values that were closer to VO_2peak and a faster time constant than adult men. These findings provide insight into the contribution and speed of response of the aerobic system during an ‘anaerobic’ test.

Key Points

• The results of this study confirm the significant contributions of the aerobic energy systems during so called ‘anaerobic tests’.
• Boys were able to attain VO₂ values from an all out 90 s sprint cycle that were closer to their aerobic VO₂ peak test than adults. More detailed studies are required to investigate the limiting factors that prevent VO₂ peak being reached in an all out sprint cycle.
• All out tests of a duration > 30 s and coupled with gas and power analyses offer paediatric physiologists considerable scope to examine the contributions of the anaerobic and aerobic energy systems until more ethically viable methods are found.

Key Words: VO_2peak, anaerobic, kinetics, aerobic, ergometry     

Degree of Trauma Differs for Major Osteoporotic Fracture Events in Older Men Versus Older Women

To examine the degree of trauma in major osteoporotic fractures (MOF) in men versus women, we used data from 15,698 adults aged ≥65 years enrolled in the Osteoporotic Fractures in Men (MrOS) study (5994 men) and the Study of Osteoporotic Fractures (SOF) (9704 women). Participants were contacted tri‐annually to ascertain incident fractures, which were confirmed by radiographic reports and coded according to degree of self‐reported trauma. Trauma was classified as low (fall from ≤ standing height; fall on stairs, steps, or curb; minimal trauma other than fall [coughing, turning over]); moderate (collisions with objects during normal activity without associated fall); or high (fall from > standing height; severe trauma [motor vehicle accident, assault]). MOF included hip, clinical vertebral, wrist, and humerus fractures. Mean fracture follow‐up was 9.1 years in SOF and 8.7 years in MrOS. A total of 14.6% of the MOF in men versus 6.3% of the MOF in women were classified as high trauma (p < 0.001); men versus women more often experienced fractures resulting from severe trauma as well as from fall > standing height. High‐trauma fractures were more significantly common in men versus women at the hip (p = 0.002) and wrist (p < 0.001) but not at the spine or humerus. Among participants with MOF, the odds ratio of a fracture related to high‐trauma fracture among men versus women was 3.12 (95% confidence interval [CI] 1.70–5.71) after adjustment for traditional risk factors. Findings were similar in analyses limited to participants with hip fractures (odds ratio [OR] = 3.34, 95% CI 1.04–10.67) and those with wrist fracture (OR = 5.68, 95% CI 2.03–15.85). Among community‐dwelling older adults, MOF are more likely to be related to high trauma in men than in women. These findings are not explained by sex differences in conventional risk factors and may reflect a greater propensity among men to engage in risky behavior. © 2015 American Society for Bone and Mineral Research.