5000 Meter Run Performance is not Enhanced 24 Hrs After an Intense Exercise Bout and Cold Water Immersion.

Cold water immersion (CWI) is used by endurance athletes to speed recovery between exercise bouts, but little evidence is available on the effects of CWI on subsequent endurance performance. The purpose of this study was to investigate the effects of CWI following an acute bout of interval training on 5000 m run performance 24 hrs after interval training, perceived muscle soreness (PMS), range of motion (ROM), thigh circumference (TC), and perceived exertion (RPE). Nine endurance-trained males completed 2 trials, each consisting of an interval training session of 8 repetitions of 1200 m at a running pace equal to 75% of VO2peak, either a control or CWI treatment, and a timed 5000 m run 24 hrs post interval training session. CWI was performed for 12 min at 12 degrees Celsius on the legs. Recovery treatments were performed in a counterbalanced design. Run time for 5000 m was not different between the CWI and control trials (CWI = 1317.33 ± 128.33 sec, control = 1303.44 ± 105.53 sec; p = 0.48). PMS increased significantly from baseline to immediately post exercise (BL = 1.17 ± 0.22, POST = 2.81 ± 0.52; p = 0.02) and remained elevated from baseline to 24 hrs post exercise (POST24 = 2.19 ± 0.32; p = 0.02), but no difference was observed between the treatments. No differences were observed for the interaction between time and treatment for TC (λ = 0.73, p = 0.15) and ROM (λ = 0.49; p = 0.10). CWI performed immediately following an interval training exercise bout did not enhance subsequent 5000 m run performance or reduce PMS. CWI may not provide a recovery or performance advantage when athletes are accustomed to the demands of the prior exercise bout.

Effects of a short-term carbohydrate-restricted diet on strength and power performance.

The purpose of the study was to examine the effects of switching from a habitual diet to a carbohydrate-restricted diet (CRD) on strength and power performance in trained men (n = 16) and women (n = 15). Subjects performed handgrip dynamometry, vertical jump, 1RM bench press and back squat, maximum-repetition bench press, and a 30-second Wingate anaerobic cycling test after consuming a habitual diet (40.7% carbohydrate, 22.2% protein, and 34.4% fat) for 7 days and again after following a CRD (5.4% carbohydrate, 35.1% protein, and 53.6% fat) for 7 days. Before both testing sessions, body weight and composition were examined using bioelectrical impedance analysis. Three 2 × 2 multiple analyses of variance were used to compare performance variables between the habitual diet and CRD. Subjects consumed significantly fewer (p < 0.05) total kilocalories during the CRD (2,156.55 ± 126.7) compared with the habitual diet (2,537.43 ± 99.5). Body mass decreased significantly (p < 0.05). Despite a reduction in body mass, strength and power outputs were maintained for men and women during the CRD. These findings may have implications for sports that use weight classes, and in which strength and power are determinants of success. A CRD may be an alternative method for short-term weight loss without compromising strength and power outputs. The use of a 7-day CRD could replace weight loss methods employing severe dehydration before competition.

Salivary estradiol, interleukin-6 production, and the relationship to substrate metabolism during exercise in females.

Estradiol (E(2)) has been documented to have anti-inflammatory effects on the immune system. Interleukin-6 (IL-6), is classified as a "myokine", and has known metabolic consequences. Thus, the purpose of this study was to determine the effects of menstrual phase and exercise on the interaction of E(2) and IL-6, and the role of IL-6 in substrate metabolism. Ten female subjects completed three separate testing sessions: baseline evaluation, and 1 h of treadmill exercise at 65% of peak [Formula: see text] during both the midfollicular (MF) and midluteal (ML) menstrual phases. Saliva was collected prior to, during, and post-exercise for determination of E(2) and IL-6. Expired gases and an additional saliva sample were collected 30 min post-exercise. No significant differences were observed in any of the measured variables across menstrual phase. Exercise resulted in an acute rise in estradiol and IL-6; however, E(2) was not related to IL-6 at baseline or in response to exercise. IL-6 remained elevated at the end of exercise and was found to be related to energy expenditure from fat, and to total energy expenditure at 60 min, and 30 min post-exercise. No relationships were found between the anti-inflammatory estrogen E(2) and the cytokine IL-6. However, relationships were found between IL-6 and indices of substrate metabolism. Based on the data from the current research, IL-6 likely plays a metabolic role in healthy individuals during exercise when released from the muscle as a result of reduced energy availability, acting as a "myokine", in comparison to inflammation-induced IL-6 release.

Development and Validation of a Functional Capacity Test for Collegiate Dancers.

The purpose of this study was to design and validate a peak functional capacity test that is physiologically comprehensive and appropriate in movement for dancers with broad dance backgrounds. The Seifert Assessment of Functional Capacity for Dancers (SAFD) employs commonly utilized dance movements in progressively intense 3-minute stages, continued until volitional exhaustion. A convenience sample of 13 female collegiate dancers completed a familiariza- tion trial of the SAFD, an SAFD trial, a peak treadmill test, and a second SAFD trial. Time to exhaustion, peak oxygen consumption (VO2 peak), respiratory exchange ratio (RER), heart rate (HR), blood lactate (BLa), and rate of perceived exertion (RPE) were measured with each trial. Intraclass correlation coefficients (ICCs) were used to assess test-retest reliability, while concurrent validity was analyzed using Pearson product-moment correlations (PPMCs). Strong ICCs were found between the SAFD trials for time to exhaustion, VO2 peak, HR, and RPE, providing evidence of test-retest reliability of the SAFD. Significant positive relationships were found between time to exhaustion, VO2 peak, HR, BLa, and RPE for the SAFD and the treadmill test, providing evidence of concurrent validity of the SAFD. The data reported in the study provide initial evidence of reliability and validity for the SAFD.

The Effects of an Acute Bout of Self-Myofascial Release on the Physiological Parameters of Running.

This study examined changes in the physiological parameters of running performance when self-myofascial release (SMR) was used prior to a submaximal run. A total of 16 male recreational runners, between the ages of 27 and 50 years old volunteered for the study. Participants had to complete a running event measuring a 10K or longer in the past 12 months and obtained a V̇O2peak value of 45 mL·kg-l · min-1 to be included in the study. Participants took part in two 40 min treadmill runs at 75% of their V̇O2peak, one session with the use of SMR and the other with 20 min of seated rest prior to the run. Measurements of heart rate, blood lactate concentrations, ventilatory efficiency (V̇E/ V̇O2), RPE, and running velocity were assessed. There was no statistically significant interaction or treatment effect for these variables when SMR was used prior to a 40 min treadmill run (p > .05; heart rate: d = .01, V̇E/ V̇O2: d = .07, RPE: d = .07). Although no positive effects on running performance were found, the lack of negative effects suggests the use of SMR prior to running does not hinder performance.

Comparing the Changes in Blood Pressure After Acute Exposure to Tai Chi and Walking.

Hypertension is a major health concern throughout the United States and is a major cause of cardiovascular disease. The purpose of this study was to compare the responses of Tai Chi and walking on measures of central and peripheral cardiac mechanisms when controlling for exercise intensity. Fifteen hypertensive subjects (2 males, 13 females; age = 20.7 ± 3.77 years; body fat = 24.26 ± 10.27%) participated in Tai Chi (TC) and walking (WK) for 30 minutes on non-consecutive days. Central systolic (CSBP) and diastolic blood pressure (CDBP), augmentation index (Alx), pulse pressure (PP), heart rate (HR), and brachial systolic (BSBP) and diastolic blood pressure (BDBP) were measured prior to exercise and following exercise every 10 minutes for a total of 60 minutes in a seated position. There were no significant differences between the two exercise forms. CSBP decreased 10 minutes after exercise in both exercise types (TC = 6.63 ± 3.258 mmHG; WK = 7 ± 4.144 mmHG p < 0.05), and 40 minutes after exercise in both exercise types (TC = 6.07 ± 3.33 mmHG; WK = 8.2 ± 3.15 mmHG, p < 0.05) compared to the initial measurement. BSBP also decreased in both exercise forms following 10 min of rest (TC = 6.99 ± 3.776 mmHG; WK = 8.8 ± 3.20 mmHG p = 0.05), and 40 min (TC = 8.46 ± 3.07 mmHG; WK = 8.87 ± 3.87 mmHG, p < 0.05) when compared to the initial resting measurement. Central aortic pressure exhibits a post exercise hypotensive (PEH) effect similar to that of peripheral blood pressure. Both Tai Chi and walking elicited similar PEH effects on systolic blood pressure in hypertensive individuals.

The Effect of Acute L-carnitine and Carbohydrate Intake on Cycling Performance.

Chronic supplementation of L-carnitine and carbohydrate has been reported to increase L-carnitine content in skeletal muscle and have positive influences on exercise variables and performance. This study investigated the acute intake of L-carnitine and carbohydrate on the exercise parameters of cycling. A total of 10 males (27.0 ± 4 years) completed two exercise sessions consisting of 40 min of cycling at 65% of VO2peak, followed by cycling to exhaustion at 85% of VO2peak. L-carnitine or a placebo was consumed 3 hours prior to exercise, and beverages consisting of 94 g of carbohydrate were consumed at both 2 hours, and 30 minutes prior to exercise. Repeated measures ANOVAs were used to compare respiratory exchange ratio (RER), blood lactate, and power output across experimental trials and time. A repeated measures t-test was used to analyze differences between conditions and time to exhaustion. RER was significantly lower (p=0.01) at baseline with L-carnitine ingestion (.83 ± .05) compared to the placebo ingestion (.86 ± .06). Blood lactate was significantly lower (p=0.02) after 10 minutes of cycling at 65% of VO2peak with ingestion of L-carnitine (35% change from baseline) compared to placebo ingestion (53% change from baseline). No differences were found for power output or time to exhaustion at 85% of VO2peak. Despite mentioned differences, acute intake of L-carnitine and carbohydrate does not appear to influence exercise parameters, likely due to a lack of sufficient change in the content of L-carnitine in skeletal muscle.

The Effect of Foam Rolling on Recovery Between two Eight Hundred Metre Runs.

With the increased popularity of foam rolling as a means of recovery, it is important to establish the exact manner in which the practice is useful. The purpose of this study was to examine the impact of foam rolling on recovery between two 800 m runs. Sixteen trained males (mean ± sd; age, 20.5 ± .5 yr; average 800 m treadmill run time, 145.2 ± 1.8 s) participated in the study, using a randomized, crossover design. The subjects completed two 800 m runs on a treadmill, separated by a 30 min rest, during which time a foam rolling protocol or passive rest period was performed. The speed of each run was as fast as possible. Subjects had access to speed controls, but were blinded to the actual speed. Blood lactate concentration and [Formula: see text]CO2 were measured prior to and following each run. Stride length, 800 m run time, and hip extension were measured during each run. [Formula: see text]CO2, stride length, 800 m run time, and hip extension were not significantly different between conditions (p > .05). For blood lactate, no statistical interaction was found between condition and time (p > .05). Foam rolling between two 800 m runs separated by 30 min performed by trained male runners does not alter performance.

Effects of betaine on body composition, performance, and homocysteine thiolactone.

BACKGROUND: This study investigated the effects of long term betaine supplementation on body composition, performance, and homocysteine thiolactone (HCTL) in experienced strength trained men. METHODS: Twenty-three subjects were matched for training experience (4.8 ± 2.3 years) and body fat percentage (BF%: 16.9 ± 8.0%), randomly assigned to either a placebo (PL; n = 12) or betaine group (BET; n = 11; 2.5 g/day), and completed a 6 week periodized training program consisting of 3 two-week micro-cycles. Bench press and back squat training volumes were recorded and changes in training volume were assessed at each micro-cycle. Fasting urine was collected at baseline (BL), weeks 2, 4 and 6, and assayed for HCTL. Subjects were tested prior to and following 6 weeks of treatment. Arm and thigh cross sectional area (CSA) was estimated via girth and skin fold measurements. Body density was estimated via skin fold calipers and used to estimate BF%, fat mass (FM), and lean body mass (LBM). Performance was assessed via vertical jump (VJ), bench press 1 RM (BP), and back squat 1 RM (BS). RESULTS: Arm CSA increased significantly (p < .05) in BET but not PL. No differences existed between group and time for changes in thigh CSA. Back squat training volume increased significantly (p < .05) for both groups throughout training. Bench press training volume was significantly (p < .05) improved for BET compared to PL at microcycles one and three. Body composition (BF%, FM, LBM) improved significantly (p < .05) in BET but not PL. No differences were found in performance variables (BP, BS, VJ) between groups, except there was a trend (p = .07) for increased VJ power in BET versus PL. A significant interaction (p < .05) existed for HCTL, with increases from BL to week 2 in PL, but not BET. Additionally, HCTL remained elevated at week 4 in PL, but not BET. CONCLUSION: Six-weeks of betaine supplementation improved body composition, arm size, bench press work capacity, attenuated the rise in urinary HCTL, and tended to improve power (p = .07) but not strength.

Influence of exercise on airway epithelia in cystic fibrosis: a review.

Regular exercise is recommended as part of cystic fibrosis (CF) physiotherapy. Exercise delays the development of pulmonary disease in CF patients; however, the cellular mechanisms responsible for these improvements are unclear. This review expands on the hypothesis that exercise improves CF pathophysiological ion dysregulation via purinergic and adrenergic pathways by describing the effects of 5' adenosine monophosphate-activated protein kinase (AMPK), atrial natriuretic peptide (ANP), and arginine-vasopressin (AVP) on CF airway epithelia. Activation of AMPK decreases Na(+) absorption, increases airway surface liquid, and reduces oxidative stress and inflammation. Plasma ANP inhibits the basolateral Na(+)/K(+)-ATPase and may therefore reduce epithelial water absorption. Airway epithelia respond to plasma AVP and secrete AVP in response to elevated bradykinin. AVP stimulates the basolateral Na(+)/K(+)/2Cl(-) exchanger, thereby increasing Cl(-) secretion, reducing Na(+) absorption, and promoting basolateral to luminal water flux. In addition, AVP may increase cilia beat frequency in airway epithelia via a Ca(2+)-dependent mechanism. This review will describe the effects of exercise on AMPK activation, ANP release, and AVP secretion; we hypothesize that the mechanical and metabolic perturbations that occur with exercise may be beneficial in preventing CF lung pathogenesis by improving airway hydration, mucociliary clearance, and reducing markers of inflammation.

Effects of physioball and conventional floor exercises on early phase adaptations in back and abdominal core stability and balance in women.

The purpose of this study was to compare the effects of 5 weeks of physioball core stability and balance exercises with conventional floor exercises in women. The experimental group (n = 15) performed curl-ups and back extensions on the physioball while the control group (n = 15) performed the same exercises on the floor. Baseline and post-training tests included electromyography (EMG) recordings of the rectus abdominus and erector spinae muscles; abdominal, back, and knee strength measurements with the Cybex Norm System; and 2 unilateral stance balance tests. The physioball group was found to have significantly greater mean change in EMG flexion and extension activity (p = 0.04 and p = 0.01, respectively) and greater balance scores (p < 0.01) than the floor exercise group. No significant changes (p > 0.05) were observed for heart rate or Cybex strength measurements. Early adaptations in a short-term core exercise program using the physioball resulted in greater gains in torso balance and EMG neuronal activity in previously untrained women when compared to performing exercises on the floor.