PMCC PMCC

Search tips
Search criteria

Advanced
Results 1-25 (261)
 

Clipboard (0)
None

Select a Filter Below

Journals
Year of Publication
more »
1.  Physical Activity and Sedentary Behaviors in Postpartum Latinas: Madres para la Salud 
Purpose
To describe the physical activity (PA) and sedentary behaviors of postpartum Latinas who are overweight or obese prior to initiating Madres para la Salud, a social-support mediated walking intervention to promote postpartum weight loss.
Methods
139 postpartum (13.6 ± 7.7 weeks since childbirth) women (age = 28.3 ± 5.6 years and BMI = 29.7 ± 3.5 kg.m2), recruited from Phoenix area Latino-serving organizations completed the Stanford Brief Activity Survey (SBAS) and concurrently wore an accelerometer (AG) and a pedometer for 7-days, and kept a PA record (PAR).
Results
Most were classified as inactive and lightly active on the SBAS (51% inactive, 37% light, 11% moderate). Most time was spent in sedentary (512.0 ± 169.9 min.d−1) and light-intensity PA (242.4 ± 51.4 min.d−1) with less time in moderate-intensity lifestyle (78.3 ± 39.9 min.d−1), moderate-intensity walking (16.6 ± 14.4 min.d−1), and vigorous-intensity PA (0.34 ± 1.5 min.d−1). Pedometer steps.d−1 were low (total = 4,973 ± 2,202 steps; aerobic = 412 ± 774 steps) with most participants rated as sedentary (61%) or low-active (28.1%). Consistent with objective PA measures, PARs showed more time spent in light-intensity PAs such as home care, cooking, child- and self care tasks, occupation, religious events, and watching television.
Conclusion
By and large, the postpartum Latinas enrolled spent most of their day in low-intensity activity levels with little time spent in health-enhancing PA levels/behaviors. This demographic should be the focus of PA interventions to increase PA to health enhancing levels.
doi:10.1249/MSS.0b013e3182863de5
PMCID: PMC3686889  PMID: 23439416
Exercise; Hispanics; Accelerometer; Physical Activity Record; Self Report Questionnaire; Pedometer
2.  Validity of ActiGraph Child-Specific Equations during Various Physical Activities 
PURPOSE
The purpose of this study was to examine the validity of seven child-specific ActiGraph prediction equations/cut-points (Crouter vector magnitude 2-regression model (Cvm2RM), Crouter vertical axis 2RM (Cva2RM), Freedson, Treuth, Trost, Puyau and Evenson) for estimating energy expenditure (EE) and time spent in sedentary behaviors, light physical activity (LPA), moderate PA (MPA), and vigorous PA (VPA).
METHODS
Forty boys and 32 girls (mean±SD; age, 12±0.8 yrs) participated in the study. Participants performed eight structured activities and approximately 2-hrs of free-living activity. Activity data was collected using an ActiGraph GT3X+, positioned on the right hip, and EE (METRMR; activity VO2 divided by resting VO2) was measured using a Cosmed K4b2. ActiGraph prediction equations were compared against the Cosmed for METRMR and time spent in sedentary behaviors, LPA, MPA, VPA, and MVPA.
RESULTS
For the structured activities, all prediction methods were significantly different from measured METRMR for ≥ 3 activities (P<0.05), however all provided close estimates of METRMR during walking. On average, participants were monitored for 95.0±36.5 minutes during the free-living measurement. The Cvm2RM and Puyau methods were within 0.9 METRMR of measured free-living METRMR (P>0.05); all other methods significantly underestimated measured METRMR (P<0.05). The Cva2RM was within 9.7 minutes of measured time spent in sedentary behaviors, LPA, MPA, and MVPA, which was the best of the methods examined. All prediction equations underestimated VPA by 6.0–13.6 minutes.
CONCLUSION
Compared to the Cosmed, the Cvm2RM and Puyau methods provided the best estimate of METRMR and the Cva2RM provided the closest estimate of time spent in each intensity category during the free-living measurement. Lastly, all prediction methods had large individual prediction errors.
doi:10.1249/MSS.0b013e318285f03b
PMCID: PMC3686914  PMID: 23439413
Motion sensor; oxygen consumption; activity counts variability; free-living activity; structured activity
3.  Walking Objectively Measured: Classifying Accelerometer Data with GPS and Travel Diaries 
Purpose
This study developed and tested an algorithm to classify accelerometer data as walking or non-walking using either GPS or travel diary data within a large sample of adults under free-living conditions.
Methods
Participants wore an accelerometer and a GPS unit, and concurrently completed a travel diary for 7 consecutive days. Physical activity (PA) bouts were identified using accelerometry count sequences. PA bouts were then classified as walking or non-walking based on a decision-tree algorithm consisting of 7 classification scenarios. Algorithm reliability was examined relative to two independent analysts’ classification of a 100-bout verification sample. The algorithm was then applied to the entire set of PA bouts.
Results
The 706 participants’ (mean age 51 years, 62% female, 80% non-Hispanic white, 70% college graduate or higher) yielded 4,702 person-days of data and had a total of 13,971 PA bouts. The algorithm showed a mean agreement of 95% with the independent analysts. It classified physical activity into 8,170 (58.5 %) walking bouts and 5,337 (38.2%) non-walking bouts; 464 (3.3%) bouts were not classified for lack of GPS and diary data. Nearly 70% of the walking bouts and 68% of the non-walking bouts were classified using only the objective accelerometer and GPS data. Travel diary data helped classify 30% of all bouts with no GPS data. The mean duration of PA bouts classified as walking was 15.2 min (SD=12.9). On average, participants had 1.7 walking bouts and 25.4 total walking minutes per day.
Conclusions
GPS and travel diary information can be helpful in classifying most accelerometer-derived PA bouts into walking or non-walking behavior.
doi:10.1249/MSS.0b013e318285f202
PMCID: PMC3674121  PMID: 23439414
Physical activity; walk trip; algorithm; classification
4.  Combined Aerobic/Strength Training and Energy Expenditure in Older Women 
Medicine and science in sports and exercise  2013;45(7):10.1249/MSS.0b013e3182860099.
Purpose
To examine the effects of three different frequencies of combined resistance and aerobic training on total energy expenditure (TEE) and activity related energy expenditure (AEE) in a group of older adults.
Methods
Seventy-two women, 60 – 74 years old, were randomly assigned to one of three groups: 1 day/week of aerobic and 1 day/week of resistance (1+1); 2 days/week of aerobic and 2 days/week resistance (2+2); or 3 days/week aerobic and 3 days/week resistance (3+3). Body composition (DXA), feeling of fatigue, depression, and vigor (questionnaire), strength (1RM), serum cytokines (ELISA), maximal oxygen uptake (progressive treadmill test), resting energy expenditure, and TEE were measured before and after 16 weeks of training. Aerobic training consisted of 40 minutes of aerobic exercise at 80% maximum heart rate and resistance training consisted of 2 sets of 10 repetitions for 10 different exercises at 80% of one repetition maximum.
Results
All groups increased fat free mass, strength and aerobic fitness and decreased fat mass. No changes were observed in cytokines or perceptions of fatigue/depression. No time by group interaction was found for any fitness/body composition variable. TEE and AEE increased with the 2+2 group but not with the other two groups. Non-exercise training AEE (NEAT) increased significantly in the 2+2 group (+200 kcal/day), group 1×1 showed a trend for an increase (+68 kcal/day) and group 3+3 decreased significantly (−150 kcal/day).
Conclusion
Results indicate that 3+3 training may inhibit NEAT by being too time consuming and does not induce superior training adaptations to 1+1 and 2+2 training. Key words: physical activity, older adults, total energy expenditure, maximum oxygen uptake.
doi:10.1249/MSS.0b013e3182860099
PMCID: PMC3713080  PMID: 23774582
5.  Effects of Running and Walking on Osteoarthritis and Hip Replacement Risk 
Purpose
Running and other strenuous sports activities are purported to increase osteoarthritis (OA) risk, more so than walking and less-strenuous activities. Analyses were therefore performed to test whether running, walking, and other exercise affect OA and hip replacement risk, and to assess BMI’s role in mediating these relationships.
Methods
Proportional hazards analyses of patients’ report of having physician-diagnosed OA and hip replacement vs. exercise energy expenditure (metabolic equivalents, METs).
Results
74,752 runners reported 2004 OA and 259 hip replacements during 7.1-year follow-up, while the 14,625 walkers reported 695 OA and 114 hip replacements over 5.7 years. Compared to running <1.8 METhr/d, the risks for OA and hip replacement decreased: 1) 18.1% (P=0.01) and 35.1% (P=0.03), respectively, for 1.8 to 3.6 METhr/d run; 2) 16.1% (P=0.03) and 50.4% (P=0.002), respectively, for 3.6 to 5.4 METhr/d run; and 3) 15.6% (P=0.02) and 38.5% (P=0.01), respectively, for ≥5.4 METhr/d run, suggesting that the risk reduction mostly occurred by 1.8 METhr/d. Baseline BMI was strongly associated with both OA (5.0% increase per kg/m2, P=2x10−8) and hip replacement risks (9.8% increase per kg/m2, P=4.8x10−5), and adjustment for BMI substantially diminished the risk reduction from running ≥1.8 METhr/d for OA (from 16.5%, P=0.01 to 8.6%, P=0.21) and hip replacement (from 40.4%, P=0.005 to 28.5%, P=0.07). The reductions in OA and hip replacement risk by exceeding 1.8 METhr/d did not differ significantly between runners and walkers. Other (non-running) exercise increased the risk of OA by 2.4% (P=0.009) and hip replacement by 5.0% per METhr/d (P=0.02), independent of BMI.
Conclusions
Whereas other exercise increased OA and hip replacement risk, running significantly reduced their risk due, in part, to running’s association with lower BMI.
doi:10.1249/MSS.0b013e3182885f26
PMCID: PMC3756679  PMID: 23377837
Prevention; exercise; epidemiology; cohort study
6.  Incident hypercholesterolemia in relation to changes in vigorous physical activity 
Purpose
Test whether changes in vigorous exercise affect the risk for hypercholesterolemia.
Methods
Incident physician-diagnosed hypercholesterolemia was compared in recreational runners whose weekly distances run increased > 0.5 km/day (4034 men, 1897 women), remained constant (±0.5 km/d; 4685 men, 1904 women), or decreased > 0.5 km/d (15,678 men, 6224 women) during 7.8 yr of prospective follow-up.
Results
Relative to those whose distance was maintained or reduced, the odds ratio (OR) (95% confidence interval) for hypercholesterolemia for those whose running increased was significantly less than 1 for men {OR: 0.82 (0.72–0.93), P = 0.0006}, women {OR: 0.71 (0.54–0.92), P = 0.01}, and men and women combined adjusted for sex {OR: 0.80 (0.72–0.89), P < 0.0001}. The significance of the odds ratios was somewhat diminished when adjusted for baseline and follow-up BMI in men {OR: 0.89 (0.79–1.01), P = 0.06}, women {OR: 0.71 (0.54–0.92), P = 0.08}, and the adjusted sexes combined {OR: 0.88 (0.79–0.98), P = 0.02}. When average distance run {i.e., (baseline + follow-up) / 2} was compared with incident hypercholesterolemia in the 6589 runners whose distance remained constant, each kilometer-per-day increment in average running distance was associated with an odds ratio significantly less than 1 in men {OR: 0.90 (0.86–0.93)}, women {OR: 0.91 (0.84–0.98)}, and the adjusted sexes combined {OR: 0.90 (0.87–0.93)}, which was also attributable in part to BMI in men {OR: 0.94 (0.90–0.97), P = 0.0005}, women {OR: 0.96 (0.89–1.04), P = 0.35}, and the adjusted sexes combined {OR: 0.94 (0.91–0.97), P = 0.0003}.
Conclusions
The odds for hypercholesterolemia: 1) decrease in runners who increase their running mileage and 2) decline in association with the higher dose of vigorous activity even in the absence of any change in exercise. These effects are associated in part to the runners’ BMI.
doi:10.1249/MSS.0b013e3181831417
PMCID: PMC4073642  PMID: 19092705
high cholesterol; prevention; running; epidemiology
7.  Greater Weight Loss from Running than Walking during 6.2-yr Prospective Follow-up 
Purpose
Test whether equivalent changes in moderate (walking) and vigorous exercise (running) produce equivalent weight loss under free-living, non-experimental conditions.
Methods
Regression analyses of changes (Δ) in BMI vs. exercise energy expenditure (ΔMETh/d, 1 metabolic equivalent or MET=3.5 ml O2•kg−1•min−1) from survey questionnaires completed at baseline and 6.2 years thereafter in 15,237 walkers and 32,216 runners.
Results
At baseline, walkers spent less energy walking than runners spent running (mean±SD males: 2.22±1.65 vs. 5.31±3.12, females: 2.15±1.63 vs. 4.76±3.03 METh/d) and walkers were significantly heavier than runners (males: 26.63±4.04 vs. 24.09±2.58, females: 25.44±5.14 vs. 21.61±2.49 kg/m2). During follow-up, energy expenditure declined less for walking in walkers than for running in runners (males: −0.19±1.92 vs. −1.27±2.87, females: −0.30±1.93 vs. −1.28±2.85 METh/d). ΔBMI was inversely related to both ΔMETh/d run and ΔMETh/d walked, but more strongly to ΔMETh/d run than walked in men, and in heavier women. Specifically, the regression coefficient for ΔBMI vs. ΔMETh/d was significantly more negative for running than walking in men in the 1st quartile (differences in slope±SE: −0.06±0.03, P=0.01), 2nd quartile (−0.10±0.03, P=0.001), 3rd quartile (−0.17±0.03, P<10−8) and 4th quartile of BMI (−0.14±0.03, P<10−4) and in the 4th BMI quartile of women (−0.32±0.04 kg/m2 per METh/d, P<10−17). This represented 90% greater weight loss per METh/d run than walked in the 4th BMI quartile for both sexes. Age-related weight gain was attenuated by running in both sexes (P<10−6), and by walking in women (P=0.005).
Conclusion
Although ΔBMI was significantly associated with both ΔMETh/d run and walked, the ΔBMI was significantly greater for Δrunning than Δwalking.
doi:10.1249/MSS.0b013e31827b0d0a
PMCID: PMC4067491  PMID: 23190592
Obesity; prevention; epidemiology; overweight
8.  Intensity Thresholds for Aerobic Exercise–Induced Hypoalgesia 
Despite many studies investigating exercise-induced hypoalgesia, there is limited understanding of the optimal intensity of aerobic exercise in producing hypoalgesic effects across different types of pain stimuli. Given that not all individuals are willing or capable of engaging in high intensity aerobic exercise, whether moderate intensity aerobic exercise is associated with a hypoalgesic response and whether this response generalizes to multiple pain induction techniques needs to be substantiated.
Purpose
This study’s purpose is to test for differences in the magnitude of pressure and heat pain modulation induced by moderate (MAE) and vigorous (VAE) intensity aerobic exercise.
Methods
Twelve healthy young males and 15 females completed one training session and three testing sessions consisting of 25 minutes of either 1) stationary cycling at 70% heart rate reserve (HRR), 2) stationary cycling at 50% HRR, or 3) quiet rest (control). Pain testing was conducted on both forearms prior to and immediately following each condition and included the following tests: pressure pain thresholds (PPT), suprathreshold pressure pain test, static continuous heat test, and repetitive pulse heat pain test. Repeated measures ANOVAs were conducted on each pain measure.
Results
VAE and MAE reduced pain ratings during static continuous heat stimuli and repetitive heat pulse stimuli, with VAE producing larger effects. VAE also increased PPTs, while neither exercise influenced suprathreshold pressure pain ratings.
Conclusion
These results suggest that MAE is capable of producing a hypoalgesic effect using continuous and repetitive pulse heat stimuli. However, a dose-response effect was evident as VAE produced larger effects than MAE.
doi:10.1249/MSS.0000000000000143
PMCID: PMC4056570  PMID: 24002342
aerobic exercise; exercise-induced analgesia; pressure pain; thermal pain; temporal summation of pain
9.  Adaptations of mouse skeletal muscle to low intensity vibration training 
Purpose
We tested the hypothesis that low intensity vibration training in mice improves contractile function of hindlimb skeletal muscles and promotes exercise-related cellular adaptations.
Methods
We subjected C57BL/6J mice to 6 wk, 5 d·wk−1, 15 min·d−1 of sham or low intensity vibration (45 Hz, 1.0 g) while housed in traditional cages (Sham-Active, n=8; Vibrated-Active, n=10) or in small cages to restrict physical activity (Sham-Restricted, n=8; Vibrated-Restricted, n=8). Contractile function and resistance to fatigue were tested in vivo (anterior and posterior crural muscles) and ex vivo on the soleus muscle. Tibialis anterior and soleus muscles were evaluated histologically for alterations in oxidative metabolism, capillarity, and fiber types. Epididymal fat pad and hindlimb muscle masses were measured. Two-way ANOVAs were used to determine effects of vibration and physical inactivity.
Results
Vibration training resulted in a 10% increase in maximal isometric torque (P=0.038) and 16% faster maximal rate of relaxation (P=0.030) of the anterior crural muscles. Posterior crural muscles were unaffected by vibration, with the exception of greater rates of contraction in Vibrated-Restricted mice compared to Vibrated-Active and Sham-Restricted mice (P=0.022). Soleus muscle maximal isometric tetanic force tended to be greater (P=0.057) and maximal relaxation was 20% faster (P=0.005) in Vibrated compared to Sham mice. Restriction of physical activity induced muscle weakness but was not required for vibration to be effective in improving strength or relaxation. Vibration training did not impact muscle fatigability or any indicator of cellular adaptation investigated (P≥0.431). Fat pad but not hindlimb muscle masses were affected by vibration training.
Conclusion
Vibration training in mice improved muscle contractility, specifically strength and relaxation rates, with no indication of adverse effects to muscle function or cellular adaptations.
doi:10.1249/MSS.0b013e3182811947
PMCID: PMC3630262  PMID: 23274599
Exercise; Fatigue; Mechanical oscillation; Strength; Whole body vibration
10.  Alterations in Osteopontin Modify Muscle Size in Females in Both Humans and Mice 
PURPOSE
An osteopontin (OPN; SPP1) gene promoter polymorphism modifies disease severity in Duchenne muscular dystrophy, and we hypothesized that it might also modify muscle phenotypes in healthy volunteers.
METHODS
Gene association studies were carried out for OPN (rs28357094) in the FAMuSS cohort (n=752; age 23.7±5.7 yrs). Phenotypes studied included muscle size (MRI), strength, and response to supervised resistance training. We also studied 147 young adults that had carried out a bout of eccentric elbow exercise (age 24.0 ± 5.2 yrs). Phenotypes analyzed included strength, soreness, and serum muscle enzymes.
RESULTS
In the FAMuSS cohort, the G allele was associated with 17% increase in baseline upper arm muscle volume only in women (F=26.32; p=5.32 × 10−7), explaining 5% of population variance. In the eccentric damage cohort, weak associations of the G allele were seen in women with both baseline myoglobin, and elevated CK. Sexually dimorphic effects of OPN on muscle were also seen in OPN null mice. Five of seven muscle groups examined showed smaller size in OPN null female mice, whereas two were smaller in males. Query of OPN gene transcription after experimental muscle damage in mice showed rapid induction within 12 hrs (100-fold increase from baseline), followed by sustained high level expression through 16 days of regeneration before falling to back to baseline.
CONCLUSION
OPN is a sexually dimorphic modifier of muscle size in normal humans and mice, and responds to muscle damage. The OPN gene is known to be estrogen responsive, and this may explain the female-specific genotype effects in adult volunteers.
doi:10.1249/MSS.0b013e31828093c1
PMCID: PMC3631433  PMID: 23274598
osteopontin (OPN); secreted phosphoprotein 1 (SPP1); genetic polymorphism; estrogen; hypertrophy; MRI
11.  Massage Timing Affects Postexercise Muscle Recovery and Inflammation in a Rabbit Model 
Purpose
This study compared the effect of immediate versus delayed massage-like compressive loading (MLL) on peak isometric torque recovery and inflammatory cell infiltration following eccentric exercise (EEX).
Methods
Eighteen skeletally mature New Zealand White rabbits were instrumented with peroneal nerve cuffs for stimulation of hindlimb tibialis anterior muscles. Following a bout of EEX, rabbits were randomly assigned to a MLL protocol (0.5Hz, 10N, 15min) started immediately post-EEX, 48 hours post-EXX, or no-MLL control and performed for four consecutive days. A torque-angle (T-Θ) relationship was obtained for 21 joint angles pre and post-EEX and post four consecutive days of MLL or no-MLL. Muscle wet weights and immunohistochemical sections were obtained following final treatments.
Results
EEX produced an average 51% (±13%) decrease in peak isometric torque output. Greatest peak torque recovery occurred with immediate application of MLL. There were differences in torque recovery between immediate and delayed MLL (p=0.0012), immediate MLL and control (p<0.0001), and delayed MLL and control (p=0.025). Immunohistochemical analysis showed 39.3% and 366.0% differences in the number of RPN3/57 and CD11b positive cells between immediate (p=0.71) and delayed MLL (p=0.12). Area under the T-Θ curve showed a difference for immediate (p<0.0001) and delayed (p=0.0051) MLL as compared to control. Exercise produced an average 10°± 0.2 rightward shift from pre exercise peak isometric torque angle. Control, immediate MLL and delayed MLL produced an average leftward angular shift from the post exercise angle (p=0.28, p=0.03, and p=0.47, respectively).
Conclusion
Post-EEX, immediate MLL was more beneficial than delayed MLL in restoring muscle function and modulating inflammatory cell infiltration. These findings invite similar human studies in order to make definitive conclusions on optimal timing of massage-based therapies.
doi:10.1249/MSS.0b013e31827fdf18
PMCID: PMC3632662  PMID: 23274593
massage; inflammation; skeletal muscle; torque-angle properties
12.  Intensive Lifestyle Modification Reduces Lp-PLA2 in Dyslipidemic HIV/HAART Patients 
Patients with dyslipidemia associated with HIV-1 infection and highly active antiretroviral therapy (HAART) have elevated levels of Lp-PLA2 and CCL5/RANTES, which may increase risk of cardiovascular disease.
Purpose
This study aimed to determine whether an intensive diet and exercise (D/E) program, independently or combined with fenofibrate or niacin, could reduce Lp-PLA2 or RANTES.
Methods
Hypertriglyceridemic HIV patients on stable HAART (n=107) were randomized to one of five interventions: 1) Usual Care (UC); 2) D/E with placebos; 3) D/E with fenofibrate and placebo; 4) D/E with niacin and placebo; or 5) D/E with fenofibrate and niacin for 24 weeks. Lp-PLA2 and RANTES concentrations were measured in fasting plasma samples at baseline and post-intervention. General linear models were used to compare Lp-PLA2 and RANTES levels between the five groups post-intervention, controlling for baseline levels, age, BMI, CD4+ T-cell count, viral load, duration of infection, and HAART.
Results
At baseline, fasting plasma Lp-PLA2 (388.5 ± 127.5 ng/mL) and RANTES (43.8 ± 25.5 ng/mL) levels were elevated when compared to healthy controls. Post-treatment Lp-PLA2 mass was lower in patients who received D/E only (323.0 ± 27.2 ng/mL), D/E plus fenofibrate (327.2 ± 25.9 ng/mL) and D/E plus niacin (311.1 ± 27.8 ng/mL) when compared to patients receiving UC (402.2 ± 25.3 ng/mL). RANTES concentrations were not significantly affected by any intervention.
Conclusions
Elevated plasma Lp-PLA2 mass can be reduced by an intensive diet and exercise program in patients with HIV/HAART-associated dyslipidemia. RANTES is elevated but is not reduced by lifestyle modification, fenofibrate or niacin.
doi:10.1249/MSS.0b013e3182843961
PMCID: PMC3655089  PMID: 23299761
platelet-activating factor acetylhydrolase; fenofibrate; niacin; dyslipidemia; RANTES
13.  Effect of Exercise on the Skeletal Muscle Proteome in Patients with Type 2 Diabetes 
Purpose
Exercise training alters protein abundance in muscle of healthy individuals, but the effect of exercise on these proteins in patients with type 2 diabetes (T2D) is unknown. The aim of this study was to determine how exercise training alters the skeletal muscle proteome in patients with T2D.
Methods
Biopsies of the vastus lateralis were obtained before and after 4 weeks of exercise training in six patients with T2D (54 ± 4 yrs, BMI 29± 2) and six age- and BMI- matched control subjects (48 ± 2, BMI 28 ± 3) studied at baseline. Proteins were identified and quantified using normalized spectral abundance factors (NSAF) by multidimensional high-resolution mass spectrometry.
Results
Of 1,329 proteins assigned at baseline, 438 were present in at least half of all muscle samples; of these, 15 proteins differed significantly between patients with T2D and control subjects (p<0.05). In the diabetic patients, exercise training altered the abundance of 17 proteins (p<0.05). Key training adaptations included an increase in proteins of the malate–aspartate shuttle and citric acid cycle, reduced abundance of glycolytic proteins, and altered abundance of cytoskeleton proteins.
Conclusion
The data from this study support the ability of exercise training to alter the abundance of proteins that regulate metabolism and cytoskeletal structure in patients with T2D. These findings open new avenues for future research.
doi:10.1249/MSS.0b013e3182814917
PMCID: PMC3660427  PMID: 23274603
PROTEOME; EXERCISE; SKELETAL MUSCLE; INSULIN RESISTANCE
14.  Walking and running are associated with similar reductions in cataract risk 
Purpose
Habitual running has been associated with reduced risk of cataract development in one prospective study. The purpose of the current analyses is to provide further evidence of this potentially important benefit of vigorous exercise, and to test whether moderate exercise (e.g., walking) provides a significant and equivalent reduction in cataract risk as vigorous exercise (e.g. running).
Methods
Cox proportional hazard analyses of self-reported, physician-diagnosed incident cataracts vs. baseline energy expenditure (metabolic equivalents or METs) in 32,610 runners and 14,917 walkers during 6.2-year follow-up. Results are reported as hazard ratios (HR), percent risk reductions (100*(HR-1)), and 95% confidence intervals (95%CI).
Results
Runners and walkers reported 733 and 1,074 incident cataracts during follow-up, respectively. When adjusted for sex, race, age, education, smoking, and intakes of meat, fruit and alcohol, lower cataract risk was significantly associated with both running (HR=0.960 per METh/d, 95%CI 0.935 to 0.986) and walking (HR=0.918 per METh/d, 95%CI: 0.881 to 0.956,), with no significant difference in the per METh/d risk reduction between running and walking, or between men and women. Compared to running or walking at or below guideline levels (≤1.8 METh/d), incident cataract risk was significantly lower for running or walking 1.8 to 3.6 (16.4% lower, 95%CI: 6.4% to 25.3%), 3.6 to 5.4 (19.0% lower, 95%CI: 5.6% to 30.4%), 5.4 to 7.2 (26.2% lower, 95%CI: 11.2% to 38.7%), 7.2 to 9.0 (34.1% lower, 95%CI: 10.0% to 51.2%), and ≥9 METh/d (41.6% lower, 95%CI: 19.8% to 57.4%).
Conclusion
Moderate (walking) and vigorous (running) exercise were both significantly associated with lower cataract risk, and their effects similar. Cataract risk appears to decrease linearly with increasing exercise energy expenditure through 9 METh/d.
doi:10.1249/MSS.0b013e31828121d0
PMCID: PMC3757559  PMID: 23274600
Vision; prevention; epidemiology; exercise
15.  Knee biomechanics during a jump-cut maneuver: Effects of gender & ACL surgery 
Purpose
The purpose of this study was to compare kinetic and knee kinematic measurements from male and female ACL-intact (ACLINT) and ACL-reconstructed (ACLREC) subjects during a jump-cut maneuver using biplanar videoradiography.
Methods
Twenty subjects were recruited; 10 ACLINT (5 males, 5 females) and 10 ACLREC (4 males, 6 females; five years post surgery). Each subject performed a jump-cut maneuver by landing on a single leg and performing a 45° side-step cut. Ground reaction force was measured by a force plate and expressed relative to body weight. Six-degree-of-freedom knee kinematics were determined from a biplanar videoradiography system and an optical motion capture system.
Results
ACLINT female subjects landed with a larger peak vertical GRF (p<0.001) compared to ACLINT male subjects. ACLINT subjects landed with a larger peak vertical GRF (p≤0.036) compared to ACLREC subjects. Regardless of ACL reconstruction status, female subjects underwent less knee flexion angle excursion (p=0.002) and had an increased average rate of anterior tibial translation (0.05±0.01%/millisecond; p=0.037) after contact compared to male subjects. Furthermore, ACLREC subjects had a lower rate of anterior tibial translation compared to ACLINT subjects (0.05±0.01%/millisecond; p=0.035). Finally, no striking differences were observed in other knee motion parameters.
Conclusion
Women permit a smaller amount of knee flexion angle excursion during a jump-cut maneuver, resulting in a larger peak vertical GRF and increased rate of anterior tibial translation. Notably, ACLREC subjects also perform the jump cut maneuver with lower GRF than ACLINT subjects five years post surgery. This study proposes a causal sequence whereby increased landing stiffness (larger peak vertical GRF combined with less knee flexion angle excursion) leads to an increased rate of anterior tibial translation while performing a jump-cut maneuver.
doi:10.1249/MSS.0b013e31827bf0e4
PMCID: PMC3594620  PMID: 23190595
kinematics; kinetics; landing stiffness; ground reaction force; anterior tibial translation; biplanar videoradiography
16.  Estimating Activity and Sedentary Behavior From an Accelerometer on the Hip or Wrist 
Previously the National Health and Examination Survey measured physical activity with an accelerometer worn on the hip for seven days, but recently changed the location of the monitor to the wrist.
PURPOSE
This study compared estimates of physical activity intensity and type with an accelerometer on the hip versus the wrist.
METHODS
Healthy adults (n=37) wore triaxial accelerometers (Wockets) on the hip and dominant wrist along with a portable metabolic unit to measure energy expenditure during 20 activities. Motion summary counts were created, then receiver operating characteristic (ROC) curves were used to determine sedentary and activity intensity thresholds. Ambulatory activities were separated from other activities using the coefficient of variation (CV) of the counts. Mixed model predictions were used to estimate activity intensity.
RESULTS
The ROC for determining sedentary behavior had greater sensitivity and specificity (71% and 96%) at the hip than the wrist (53% and 76%), as did the ROC for moderate to vigorous physical activity on the hip (70% and 83%) versus the wrist (30% and 69%). The ROC for the CV associated with ambulation had a larger AUC at the hip compared to the wrist (0.83 and 0.74). The prediction model for activity energy expenditure (AEE) resulted in an average difference of 0.55 (+/− 0.55) METs on the hip and 0.82 (+/− 0.93) METs on the wrist.
CONCLUSIONS
Methods frequently used for estimating AEE and identifying activity intensity thresholds from an accelerometer on the hip generally do better than similar data from an accelerometer on the wrist. Accurately identifying sedentary behavior from a lack of wrist motion presents significant challenges.
doi:10.1249/MSS.0b013e31827f0d9c
PMCID: PMC3631449  PMID: 23247702
Activity monitor; accelerometer; mobile phones; thresholds; coefficient of variation; sedentary behavior; exercise
17.  Maternal exercise improves insulin sensitivity in mature rat offspring 
Purpose
Recent findings have shown the intrauterine environment can negatively influence long-term insulin sensitivity in the offspring. In an attempt to be pro-active, we set out to explore maternal voluntary exercise as an intervention in order to improve offspring insulin sensitivity and glucose homeostasis.
Methods
Female Sprague Dawley rats were split into sedentary and exercise groups with the exercise cohort having voluntary access to a running wheel in the cage prior to and during mating, pregnancy, and nursing. Female offspring were weaned into sedentary cages. Glucose tolerance tests and hyperinsulinemic–euglycemic clamp were performed in adult offspring to evaluate glucose regulation and insulin sensitivity.
Results
Adult female offspring born to exercised dams had enhanced glucose disposal during glucose tolerance testing (P < 0.05) as well as increased glucose infusion rates (P < 0.01) and whole body glucose turnover rates (P < 0.05) during hyperinsulinemic–euglycemic clamp testing compared to offspring from sedentary dams. Offspring from exercised dams also had decreased insulin levels (P < 0.01) and hepatic glucose production (P < 0.05) during the clamp procedure compared to offspring born to sedentary dams. Offspring from exercised dams had increased glucose uptake in skeletal muscle (P < 0.05) and decreased heart glucose uptake (P < 0.01) compared to offspring from sedentary dams in response to insulin infusion during the clamp procedure.
Conclusions
Exercise during pregnancy enhances offspring insulin sensitivity and improves offspring glucose homeostasis. This can decrease offspring susceptibility to insulin resistant related disease such as type 2 diabetes mellitus. Maternal exercise could be an easy, short–term, non–pharmacological method of preventing disease in future generations.
doi:10.1249/MSS.0b013e31827de953
PMCID: PMC3617068  PMID: 23247711
Pregnancy; running; programming; hyperinsulinemic-euglycemic clamp; rat
18.  Physical Activity and Cardiovascular Disease in African Americans in ARIC 
Purpose
Although there is substantial evidence that physical activity reduces a person's risk of cardiovascular disease (CVD), few of these studies have included African Americans. The studies that have included African Americans offer inconclusive evidence on the association and none studied heart failure separately. We used data from the Atherosclerosis Risk in Communities study cohort to examine, in African Americans, the association of physical activity with the incidence of CVD and its major components – stroke, heart failure, and coronary heart disease.
Methods
Participants aged 45 to 64 years (3,707 African Americans and, for comparison, 10,018 Caucasians) had physical activity assessed via questionnaire in 1987 and were followed for incident CVD (n=1,039) through 2008.
Results
After adjustment for potential confounders, physical activity was inversely related to CVD, heart failure, and coronary heart disease incidence in both races (p-values for trend <.0001), and with stroke in African Americans. Hazard ratios (95% confidence intervals) for CVD for each higher physical activity category were similar by race: 1.0, 0.65 (0.56, 0.75), and 0.59 (0.49, 0.71) for African Americans and 1.0, 0.74 (0.66, 0.83), and 0.67 (0.59, 0.75) for Caucasians (p-value for interaction = 0.38).
Conclusions
Our findings reinforce recommendations that regular physical activity is important for CVD risk reduction in African Americans as well as Caucasians and support the idea that some physical activity is better than none.
doi:10.1249/MSS.0b013e31827d87ec
PMCID: PMC3622814  PMID: 23247714
exercise; stroke; coronary heart disease; heart failure; race
19.  Advances in Exercise, Fitness, and Performance Genomics in 2012 
A small number of excellent papers on exercise genomics issues have been published in 2012. A new PYGM knock-in mouse model will provide opportunities to investigate the exercise intolerance and very low activity level of people with McArdle disease. New reports on variants in ACTN3 and ACE have increased the level of uncertainty regarding their true role in skeletal muscle metabolism and strength traits. The evidence continues to accumulate on the positive effects of regular physical activity on body mass index (BMI) or adiposity in individuals at risk of obesity as assessed by their FTO genotype or by the number of risk alleles they carry at multiple obesity-susceptibility loci. Serum levels of triglycerides and the risk of hypertriglyceridemia were shown to be influenced by the interactions between a single nucleotide polymorphism (SNP) in the NOS3 gene and physical activity level. Allelic variation at nine SNPs was shown to account for the heritable component of the changes in submaximal exercise heart rate induced by the HERITAGE Family Study exercise program. SNPs at the RBPMS, YWHAQ, and CREB1 loci were found to be particularly strong predictors of the changes in submaximal exercise heart rate. The 2012 review ends with comments on the importance of relying more on experimental data, the urgency of identifying panels of genomic predictors of the response to regular exercise and particularly of adverse responses, and the exciting opportunities offered by recent advances in our understanding of the global architecture of the human genome as reported by the ENCODE project.
doi:10.1249/MSS.0b013e31828b28a3
PMCID: PMC3640622  PMID: 23470294
Genetics; exercise training; physical activity; candidate genes; gene–exercise interaction; single nucleotide polymorphism; quantitative trait locus; genomic predictors
20.  Lifestyle Intervention Improves Fitness Independent of Metformin in Obese Adolescents 
Purpose
Obesity in adolescence increases the risk for early adult cardiovascular disease. We recently showed that 6 months of diet, exercise, and metformin resulted in reductions in adiposity and that diet/exercise alone reduced proinflammatory factors and intrahepatic fat in pubertal children with uncomplicated obesity. The purpose of the present study was to determine whether changes in cardiorespiratory fitness (CRF) after 6 months of structured diet and exercise (DE) or DE plus metformin are related to the previously observed changes in adiposity, markers of inflammation, and intrahepatic fat.
Methods
Sixteen obese pubertal adolescents between the ages of 10 and 17 were randomized into a structured lifestyle program consisting of DE or DE plus metformin. Subjects performed aerobic and resistance exercise 3 d·wk−1, 30 min per session. Cycle ergometer maximal oxygen consumption (V̇O2max), body composition, blood markers (glucose, insulin, homeostatic model assessment–insulin resistance, interleukin-6, hsCRP), and intrahepatic fat were measured at baseline and 6 months.
Results
In the cohort, as whole-body weight decreased by 4.0% (P = 0.009), body mass index decreased by 4.9% (P = 0.003), percent body fat decreased by 8.8% (P < 0.001), and V̇O2max improved in 10 of 16 subjects. The addition of metformin provided no further effect on body composition, CRF, or inflammatory factors. More favorable changes in adiposity, adiponectin, and a trend toward blood glucose and interleukin-6 concentrations (P = 0.07) were observed in subjects who increased V̇O2max at 6 months (n = 10) compared with no change in these variables in those who did not improve V̇O2max.
Conclusions
Metformin did not provide benefits above lifestyle modification for improving CRF in obese adolescents. Improvements in V̇O2max seem to be associated with more favorable metabolic outcomes.
doi:10.1249/MSS.0b013e31823cef5e
PMCID: PMC3998746  PMID: 22015710
PUBERTY; V̇O2MAX; BODY COMPOSITION; METABOLIC SYNDROME
21.  Advances in Exercise, Fitness, and Performance Genomics in 2011 
This review of the exercise genomics literature emphasizes the highest quality papers published in 2011. Given this emphasis on the best publications, only a small number of published papers are reviewed. One study found that physical activity levels were significantly lower in patients with mitochondrial DNA mutations compared to controls. A two-stage fine mapping follow-up of a previous linkage peak found strong associations between sequence variation in the activin A receptor, type-1B (ACVR1B) gene and knee extensor strength, with rs2854464 emerging as the most promising candidate polymorphism. The association of higher muscular strength with the rs2854464 A-allele was confirmed in two separate cohorts. A study using a combination of transcriptomic and genomic data identified a comprehensive map of the transcriptomic features important for aerobic exercise training-induced improvements in maximal oxygen consumption, but no genetic variants derived from candidate transcripts were associated with trainability. A large-scale de novo meta-analysis confirmed that the effect of sequence variation in the fat mass and obesity-associated (FTO) gene on the risk of obesity differs between sedentary and physically active adults. Evidence for gene-physical activity interactions on type 2 diabetes risk was found in two separate studies. A large study of women found that physical activity modified the effect of polymorphisms in the lipoprotein lipase (LPL), hepatic lipase (LIPC), and cholesteryl ester transfer protein (CETP) genes, identified in previous genome-wide association study (GWAS) reports, on HDL-C. We conclude that a strong exercise genomics corpus of evidence would not only translate into powerful genomic predictors but would also have a major impact on exercise biology and exercise behavior research.
doi:10.1249/MSS.0b013e31824f28b6
PMCID: PMC3994883  PMID: 22330029
Genetics; exercise training; candidate genes; gene-exercise interaction; single nucleotide polymorphism; quantitative trait locus; genomic predictors
22.  Aspirin and Clopidogrel Alter Core Temperature and Skin Blood Flow during Heat Stress 
Antithrombotic therapy with oral aspirin or clopidogrel (PlavixR) is associated with an attenuated skin vasodilator response and a greater rate of rise in core temperature in healthy, middle-aged individuals during passive heating in a water perfused suit.
Purpose
The present double-blind, crossover study examined the functional consequences of 7 days of low-dose aspirin (ASA, 81 mg/day) vs. clopidogrel (CLO, 75 mg/day) treatment in 14 healthy, middle-aged (50–65 yrs) men and women during passive heating in air (40 min at 30°C, 40% rh) followed by exercise (60% V̇O2peak).
Methods
Oral temperature (Tor) was measured in the antechamber (23.0 ± 0.1°C) before entering a warm environmental chamber. After 40 minutes of rest subjects cycled on a recumbent cycle ergometer for up to 120 minutes. Esophageal temperature (Tes) and laser Doppler flux were measured continuously, and the latter was normalized to maximal cutaneous vascular conductance (%CVCmax).
Results
Prior to entry into the environmental chamber there were no differences in Tor among treatments; however, after 40 minutes of rest in the heat, Tes was significantly higher for ASA and CLO vs. placebo (37.2±0.1°C, 37.3±0.1°C, vs. 37.0±0.1°C, both P<0.001), a difference that persisted throughout exercise (P<0.001 vs. placebo). The mean body temperature thresholds for the onset of cutaneous vasodilation were shifted to the right for both ASA and CLO during exercise (P<0.05).
Conclusion
ASA and CLO resulted in elevated core temperatures during passive heat stress and shifted the onset of peripheral thermoeffector mechanisms toward higher body temperatures during exercise heat stress.
doi:10.1249/MSS.0b013e31827981dc
PMCID: PMC3594134  PMID: 23135368
acetylsalicylic acid; PlavixR; esophageal temperature; laser Doppler flowmetry
23.  Influence of diet, exercise and serum vitamin D on sarcopenia in post-menopausal women 
Purpose
To investigate the effects of 12 months of dietary weight loss and/or aerobic exercise on lean mass and the measurements defining sarcopenia in postmenopausal women, and to examine the potential moderating effect of serum 25-hydroxyvitamin D (25(OH)D) and age.
Methods
439 overweight and obese postmenopausal women were randomized to: diet modification (N=118); exercise (N=117), diet+exercise (N=117), or control (N=87). The diet intervention was a group-based program with a 10% weight loss goal. The exercise intervention was 45 mins/day, 5 days/week of moderate-to-vigorous intensity aerobic activity. Total and appendicular lean mass were quantified by dual Xray absorptiometry (DXA) at baseline and 12 months. A skeletal muscle index (SMI=appendicular lean mass (kg)/m2) and the prevalence of sarcopenia (SMI<5.67 kg/m2) were calculated. Serum 25(OH)D was assayed using a competitive chemiluminescent immunoassay.
Results
Dietary weight loss resulted in a significant decrease in lean mass, and a borderline significant decrease in appendicular lean mass and SMI compared to controls. In contrast, aerobic exercise significantly preserved appendicular lean mass and SMI. Diet + exercise attenuated the loss of appendicular lean mass and SMI compared to diet alone, and did not result in significant loss of total- or appendicular lean mass compared to controls. Neither serum 25(OH)D nor age were significant moderators of the intervention effects.
Conclusions
Aerobic exercise added to dietary weight loss can attenuate the loss of appendicular lean mass during weight loss, and may be effective for the prevention and treatment of sarcopenia among overweight and obese postmenopausal women.
doi:10.1249/MSS.0b013e31827aa3fa
PMCID: PMC3594522  PMID: 23190588
caloric restriction; weight loss; 25-hydroxyvitamin D; ageing
24.  Subconcussive Head Impact Biomechanics: Comparing Differing Offensive Schemes 
Recent literature suggests that sub-concussive impacts may influence cognitive functioning across the lifespan. These effects are suggested to manifest as functional and possibly structural changes. Head impact biomechanics during American football have been characterized from the high school to professional level, but style of play has not been considered.
Purpose
The aim of this investigation was to quantify and compare head impact frequencies and magnitudes between two different offensive schemes.
Methods
We investigated the frequencies and magnitudes (linear acceleration [g], rotational acceleration [rad/s2], and HITsp) of head impacts sustained by 83 high school football athletes, playing for schools employing two different offensive schemes. The two schemes comprised of a run first offense (42 athletes) and a pass first offense (41 athletes). The Head Impact Telemetry System was used to record head impact measures.
Results
A total of 35,620 impacts were recorded across two seasons. Athletes in the run first offense sustained an average of 456 head impacts per season (41 practices and 9 games) while the pass first offense athletes sustained an average of 304 head impacts per season (44 practices and 9 games). The pass first offense however sustained significantly higher impact magnitudes (p’s<0.05; 28.56g, 1777.58rad/s2, and 16.24) than the run first offense (25.67g, 1675.36rad/s2, and 15.48) across a season.
Conclusion
These data provide a first look at how different offensive strategies may influence head impact exposure in football athletes. In the study population, a run first offense was associated with more frequent head impacts, of smaller magnitude, than a pass first offense.
doi:10.1249/MSS.0b013e3182798758
PMCID: PMC3605196  PMID: 23135370
25.  Physical Activity, Genes for Physical Fitness, and Risk of Coronary Heart Disease 
Purpose
Both physical activity and physical fitness are associated with decreased coronary heart disease (CHD) risk. Our objective was to determine whether genes associated with physical fitness modify the association between physical activity and CHD.
Methods
We conducted a prospective cohort study among 23,016 initially healthy women in the Women’s Genome Health Study. Leisure-time physical activity was reported at entry and during follow-up. 58 single nucleotide polymorphisms associated with physical fitness were identified from published literature and summed to create four separate genetic scores related to phenotypes of endurance, muscle strength, VO2max, and overall fitness.
Results
During a median of 14.4 years, 320 incident CHD events occurred. Increased physical activity was associated with lower CHD risk in multivariable-adjusted models (P = 0.0008). Independent of physical activity, only muscle strength genetic score was inversely associated with CHD risk (P = 0.05). There was no evidence that the inverse relation between physical activity and CHD was modified by any of the genetic scores for physical fitness. For overall fitness genetic score, the hazard ratio (HR) per 500 kcal/week of physical activity was 0.85 (95% CI: 0.72, 1.00) in the highest quartile of genetic score; 0.79 (95% CI: 0.67, 0.92) in the lowest quartile (P, interaction = 0.50). For VO2max genetic score, the HR was 0.86 (95% CI 0.72, 1.02) and 0.84 (95% CI 0.72, 0.98), respectively (P, interaction = 0.59).
Conclusions
In this large prospective cohort of women, genes associated with physical fitness did not modify the inverse association between physical activity and CHD risk.
doi:10.1249/MSS.0b013e3182784e9f
PMCID: PMC3605203  PMID: 23073218
exercise; epidemiology; genetics; cardiovascular disease

Results 1-25 (261)