Samuel Headley

Exercise training improves HR responses and V˙O2peak in predialysis kidney patients.

PURPOSE The current pilot and feasibility study was designed to examine the effect of 48 wk of moderate-intensity exercise training and dietary modification on kidney function and vascular parameters in chronic kidney disease (CKD) patients. METHODS Twenty-one stage 2-4 CKD patients (age, 18-70 yr) were randomly assigned to either the training group (TG, n = 10) or the usual care group (n = 11) for 48 wk. The TG received 48 wk of personal training (3 d·wk for up to 55 min per session at 50%-60% V˙O2peak) and dietary counseling, whereas individuals in the usual care group received standard of care and were instructed not to start a structured exercise program while in the study. V˙O2peak, estimated glomerular filtration rate (eGFR), resting and ambulatory HR, plasma lipids (total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides), and inflammatory markers (high-sensitivity C-reactive protein and interleukin 6) were assessed at baseline and weeks 24 and 48. An independent groups t-test was used to compare glomerular filtration rate slopes between groups, whereas all other data were analyzed with ANCOVA using the baseline value as the covariate. RESULTS There were no statistically significant differences in any of the parameters at baseline. The 48-wk intervention led to a significant increase in V˙O2peak, reductions in both resting and ambulatory HR, and increases in LDL cholesterol and in TG, but it had no effect on the rate of change of eGFR over time. CONCLUSIONS A 48-wk exercise training program, primarily focused on aerobic exercise, increases V˙O2peak and favorably alters autonomic function as evidenced by reductions in HR in stages 2-4 CKD patients. The exercise intervention had no effect on kidney function as assessed by eGFR.

Lack of circulating bioactive and immunoreactive IGF-I changes despite improved fitness in chronic kidney disease patients following 48 weeks of physical training

OBJECTIVE As known abnormalities exist in the insulin-like growth factor (IGF) system in chronic kidney disease (CKD) patients, the measurement of bioactive IGF-I may provide further insight into the therapeutic potential of long-term exercise training. DESIGN Patients (N=21) with stages 3 and 4 CKD were recruited from a local nephrology practice in Springfield, MA and randomized into matched treatment and control groups. The treatment group participated in 48 weeks of supervised, progressive exercise training and dietary counseling, while the control group received only usual care. Treadmill testing, anthropometric measurements, and blood samples for analysis of immunoreactive IGF-I, IGF-II, IGFBP-1 and -2, and bioactive IGF-I were taken at baseline, 24 weeks, and 48 weeks. RESULTS There were no significant differences in any of the components of the IGF system (all p-values>0.05). Immunoreactive IGF-I levels correlated significantly with bioactive IGF-I at baseline (r=0.50, p=0.02) and at 48 weeks (r=0.64, p=0.01). There was a significant interaction between group and time for both VO(2peak) (p=0.03) and total treadmill time (TT) (p<0.01). CONCLUSIONS Despite improvements in physical performance, a 48-week training program did not affect any of the circulating IGF system measurements. Disparities between these findings and those of other researchers reporting a biphasic response to long-term training may be explained by differences in study groups and exercise programs.

Effects of Lifting Tempo on One Repetition Maximum and Hormonal Responses to a Bench Press Protocol

Headley, SA, Henry, K, Nindl, BC, Thompson, BA, Kraemer, WJ, and Jones, MT. Effects of lifting tempo on one repetition maximum and hormonal responses to a bench press protocol. J Strength Cond Res 25(2): 406-413, 2011-This study was carried out in 2 parts: part 1 was designed to measure the 1 repetition maximum (1RM) bench press with 2 different moderate-velocity tempos (2/0/2) vs. (2/0/4) in male lifters while part 2 compared the hormonal responses at the same tempos as described in part 1. In both parts 1 and 2, the 1RMs (lbs) were higher on the 2/0/2 tempo than on the 2/0/4 tempo. The change in plasma volume (PV) was greater after the 2/0/4 tempo (−5.7 ± 1.7% vs. 0.96 ± 1.2%, p < 0.05). All blood parameters were significantly (p < 0.05) higher post-exercise compared with baseline. With PV corrected, insulin-like growth factor 1 (IGF-1) (ng·mL−1) was higher with the 2/0/2 tempo only (pre-exercise: 277.4 ± 21.8, post-exercise: 308.1 ± 22.9; 2/0/4 tempo pre-exercise: 277.2 ± 17.6, post-exercise: 284.8 ± 21.2). In conclusion, heavier loads can be lifted and more total work can be performed using a (2/0/2) tempo compared with a slower (2/0/4) tempo, but with the exception of IGF-1, the hormonal responses are similar. Individuals may get the same metabolic responses to training by using different tempos, but they will need to use less weight at a slower tempo.

The effects of yoga training and a single bout of yoga on delayed onset muscle soreness in the lower extremity.

The purpose of this study was to determine the effects of yoga training and a single bout of yoga on the intensity of delayed onset muscle soreness (DOMS). 24 yoga-trained (YT; n = 12) and non–yoga-trained (CON; n = 12), matched women volunteers were administered a DOMS-inducing bench-stepping exercise. Muscle soreness was assessed at baseline, 24, 48, 72, 96, and 120 hours after bench-stepping using a Visual Analog Scale (VAS). Groups were also compared on body awareness (BA), flexibility using the sit-and-reach test (SR), and perceived exertion (RPE). Statistical significance was accepted at p ≤ 0.05. A 2 × 2 mixed factorial ANOVA with repeated measures at 24 and 48 hours revealed a significant (p < 0.05) group main effect with VAS scores greater for CON than YT. Paired t-tests revealed that in YT, VAS scores were higher before yoga class than after yoga class at 24 hours (21.4 [± 6.9] mm vs. 11.1 [± 4.1] mm; p = 0.02). The SR was greater in YT than in CON (65.0 [± 7.9] cm vs. 33.3 [± 7.0] cm; p < 0.01); however, no differences were found between yoga and control in BA (94.0 [± 4.4] units vs. 83.8 [± 3.7] units; p = 0.21) or in RPE at 5-minute intervals (2.9 [± 0.3], 5.3 [± 0.8], 5.8 [± 0.9], and 5.2 [± 0.8] vs. 2.5 [± 0.3], 4.0 [± 0.5], 4.2 [± 0.3], and 4.9 [± 0.4]. Yoga training and a single bout of yoga appear to attenuate peak muscle soreness in women following a bout of eccentric exercise. These findings have significant implications for coaches, athletes, and the exercising public who may want to implement yoga training as a preseason regimen or supplemental activity to lessen the symptoms associated with muscle soreness.

Effects of unilateral and bilateral lower-body heavy resistance exercise on muscle activity and testosterone responses.

Abstract Jones, MT, Ambegaonkar, JP, Nindl, BC, Smith, JA, and Headley, SA. Effects of unilateral and bilateral lower-body heavy resistance exercise on muscle activity and testosterone responses. J Strength Cond Res 26(4): 1094–1100, 2012—Unilateral and bilateral lower-body heavy resistance exercises (HREs) are used for strength training. Little research has examined whether muscle activation and testosterone (TES) responses differ between these exercises. Our purpose was to compare the effects of unilateral and bilateral lower-body HRE on muscle activity using surface electromyography (sEMG) and TES concentrations. Ten resistance-trained, college-aged male athletes (football, track and field) completed 5 testing sessions in which bilateral (back squat [BS]) and unilateral (pitcher squat [PS]) exercises were performed using a counterbalanced design. Sessions 1 and 2 determined estimated maximum strength (10 repetition maximum [10RM]) in the BS and PS. During testing session 3, muscle activation (sEMG) was measured in the right vastus lateralis, biceps femoris, gluteus maximus, and erector spinae (ES) during both BS and PS (stance leg) exercises. In sessions 4 and 5, total TES concentrations (nanomoles per liter) were measured via blood draws at baseline (preexercise), 0, 5, 10, 15, and 30 minutes postexercise after 4 sets of 10 repetitions at the 10RM. Separate repeated-measures analyses of variance examined differences in sEMG and TES between BS and PS (p < 0.05). The sEMG amplitudes were similar (p = 0.80) for BS (0.22 ± 0.06 mV) and PS (0.20 ± 0.07 mV). The TES responses were also similar (p = 0.15) between BS (21.8 ± 6.9 nmol·L−1) and PS (26.2 ± 10.1 nmol·L−1). The similar lower limb and back sEMG and TES responses may indicate that the neuromuscular and hormonal demands were comparable for both the BS and PS exercises despite the absolute work being less in the PS. The PS exercise may be an effective method for including unilateral exercise into lower-body resistance training when designing training programs for ground-based activities.

Immediate blood pressure-lowering effects of aerobic exercise among patients with chronic kidney disease

Aim:  The current study was designed to determine the effect of moderate‐intensity aerobic exercise on blood pressure responses within the laboratory for 60 min post exercise and in the subsequent 24 h period in patients with chronic kidney disease.

Effects of dietary macronutrient distribution on vascular integrity in obesity and metabolic syndrome.

Metabolic syndrome is a condition characterized by a clustering of risk factors for cardiovascular disease. Emerging data suggest vascular integrity is disrupted in metabolic syndrome. Vascular integrity may be determined using several measurements, including pulse wave velocity, augmentation index, and flow-mediated dilation. Arterial stiffness has become an important clinical indicator of cardiovascular disease risk. Several circulating inflammatory peptides also impact vascular integrity. The present review examines the efficacy of nutritional interventions aimed at improving vascular integrity and reducing levels of associated inflammatory peptides in individuals with metabolic syndrome, with a specific focus on the effect of dietary macronutrient redistribution on these factors.

The Effects of Chronic Aerobic Exercise on Cardiovascular Risk Factors in Persons with Diabetes Mellitus

Purpose of ReviewAerobic exercise training is a component of diabetes mellitus (DM) care guidelines due to its favorable effects on glycemic control and cardiovascular disease (CVD) risk factors. The purpose of this review is to outline the recent evidence regarding the clinical effects of chronic aerobic exercise on CVD risk factors in persons with DM and to compare the effects of varying intensities and types of exercise.Recent FindingsAmong individuals with DM, all types of aerobic exercise training can impact positively on some traditional and non-traditional risk factors for CVD. Training programs with a higher volume or intensity induce greater improvements in vascular function, cardiorespiratory fitness (CRF), and lipid profiles.SummaryThe beneficial outcomes of aerobic training include improvements in glycemic control, endothelial function, oxidative stress, dyslipidemia, myocardial function, adiposity, and CRF. Findings regarding markers of inflammation are discrepant and further research should focus on the role of exercise to impact upon the chronic inflammation associated with DM.

Preservation of Fat-Free Mass After Two Distinct Weight Loss Diets with and without Progressive Resistance Exercise

BACKGROUND Preserving fat-free mass (FFM) during weight loss is important in older adults. The purpose was to examine a low-fat diet (LFD) versus a carbohydrate-restricted diet (CRD) with and without progressive resistance exercise (PRE) on preservation of FFM in older men with metabolic syndrome. METHODS A total of 42 men (59±7 years) were matched [body mass index (BMI)] and randomized to LFD, LFD&PRE, CRD, and CRD&PRE. PRE groups performed supervised strength training three times per week. Body weight, composition, metabolic syndrome criteria, and strength were measured at baseline and week 12. A 3-day diet record was kept at baseline and at weeks 1, 6, and 12. RESULTS Attrition (24%) was similar between groups. Depicted as % carbohydrate:fat:protein, the intervention diet was: LFD=55:24:18, LFD&PRE=57:20:20, CRD=16:54:28, and CRD&PRE=12:56:31. Weight (lb) decreased similarly in all groups (LFD, -18.0±7.4; LFD&PRE, -19.8±12.8; CRD, -20.2±8.0; CRD&PRE, -22.7±6.0; P<0.001), and number of participants with metabolic syndrome decreased in all groups (-3, -6, -3, -4, respectively). Percent of weight loss from appendicular FFM was 27.5%, 15.9%, 15.7%, and 17.3% respectively. A trend was found when comparing LFD and LFD&PRE (P=0.068), and when comparing LFD&CRD (P=0.072). Triglycerides improved more for the LFD&PRE, CRD, and CRD&PRE groups compared to the LFD group (P<0.05). Improvements in high-density lipoprotein-cholesterol were better in the CRD&PRE group (4.1±5.1 mg/dL) versus the LFD group (-5.0±5.9 mg/dL; P<0.01). CONCLUSIONS LFD&PRE, CRD, and CRD&PRE preserve FFM similarly. PRE is an important component of a LFD during weight loss in this population.

Blood pressure response to acute and chronic exercise in chronic kidney disease

The current study was designed to determine if a relationship exists between acute and chronic blood pressure responses to aerobic exercise in pre‐dialysis patients.