Intensity Of Sessions Research Articles

Oxygen Consumption during Different Exercise Protocols in the Aged

Objectives: The objective of this study was to compare response; specifically oxygen consumption; of a single bout of exercise using two different (constant and interval) intensity protocols in an aged population. Design: Ten males (68.8 ± 3.7 years) and six females (66.2 ± 3.5 years) were recruited for this study. All participants were actively involved in three hours of physical activity per week and were able to use a cycle ergometer unaided. Methods: Participants completed two randomised 20 min exercise protocols on a cycle ergometer, each with equal work output. The constant intensity session was at 50% of Vo2max, and the 1 min interval session varied from 70% to 30% Vo2max. Oxygen consumption was measured during the following phases; resting, warm-up, exercise, cooldown and 20 mins post-exercise. Results: Similar values were found when comparing the overall oxygen consumption for the constant and interval protocols respectively. However, significant differences (p<0.05) were found between the two different intensities during the exercise phase. Conclusions: The interval training protocol consumed higher levels of oxygen during the exercise phase when compared to the constant intensity protocol, despite the participants reporting similar RPE. These age-specific differences should be considered for future exercise prescription for this at-risk population.

Lombalgia durante a gestação: eficácia do tratamento com Reeducação Postural Global (RPG)

Realizou-se um estudo clínico comparativo com o objetivo de avaliar o efeito da Reeducação Postural Global (RPG) no tratamento da lombalgia durante a gravidez e sua relação com limitações funcionais das gestantes. Os sujeitos foram 34 gestantes nulíparas atendidas em três centros de saúde e um hospital privado de Campinas, com idade gestacional entre 20 e 25 semanas e queixa de dor lombar. Dezessete gestantes foram submetidas a sessões de RPG durante oito semanas consecutivas, e as demais seguiram orientações de rotina para controle da dor lombar. Em cada sessão de RPG avaliou-se a intensidade da dor percebida pela mulher, antes e após os procedimentos. O grupo controle foi avaliado quanto à intensidade da dor na admissão, às quatro e oito semanas do estudo. Aplicou-se o questionário Roland-Morris para avaliar limitações funcionais, ao início e final do acompanhamento. O grupo de RPG apresentou decréscimo estatisticamente significativo na intensidade da dor antes e depois das sessões. Ao longo do estudo, as mulheres submetidas a RPG tiveram medianas de intensidade da dor e médias do escore de limitações funcionais significativamente menores que as do grupo controle. Análise de covariância indicou que o tratamento com RPG estava associado à menor intensidade da dor percebida ao final do estudo. Conclui-se que a RPG pode dar importante contribuição no tratamento da dor lombar durante a gestação, reduzindo, ao mesmo tempo, as limitações funcionais.

Acute Effects of Different Intensity Treadmill Exercise on Obesity Risk Factors in Overweight Males

PURPOSE: The purpose of present study was to investigate the acute effects of different intensity treadmill exercise on blood lipids, atherosclerosis index (AI), insulin resistance (homeostatic model assessment index; HOMA index), and energy metabolism in overweight college-aged males. METHODS: Subjects were randomly assigned to either a moderate intensity (n=6, 60-70% HRmax) or high intensity (n=6, 70-80% HRmax) treadmill exercise session that lasted for one hour. Blood lipids, AI, and HOMA index was assessed before and after the one hour exercise session. Data were analyzed by paired and independent t-tests and statistical significance was set at p<0.05. RESULTS: Total cholesterol, HDL-C, LDL-C, glucose levels, and triglycerides, as well as the HOMA index and AI remained unchanged after completion of both the moderate and high intensity exercise sessions. Insulin levels were significantly (p<0.05) decreased following the high intensity exercise protocol but remained unaltered after the moderate intensity session. Both exercise protocols resulted in significant (p<0.05) increases in total protein and free-fatty acid levels. CONCLUSIONS: Exercise intensity does not alter the lack of responses to a single, acute bout of aerobic exercise, reinforcing the importance of the need for long term aerobic exercise programs when targeting weight control and the prevention of obesity.

Cardiovascular and autonomic responses after exercise sessions with different intensities and durations

BACKGROUND:Several studies have reported the phenomenon of post-exercise hypotension. However, the factors that cause this drop in blood pressure after a single exercise session are still unknown.OBJECTIVE:To investigate the effects of aerobic exercise on the acute blood pressure response and to investigate the indicators of autonomic activity after exercise.METHODS:Ten male subjects (aged 25 ± 1 years) underwent four experimental exercise sessions and a control session on a cycle ergometer. The blood pressure and heart rate variability of each subject were measured at rest and at 60 min after the end of the sessions.RESULTS:Post-exercise hypotension was not observed in any experimental sessions (P > 0.05). The index of parasympathetic neural activity, the RMSSD, only remained lower than that during the pre-exercise session after the high-intensity session (Δ = -19 ± 3.7 for 15-20 min post-exercise). In addition, this value varied significantly (P < 0.05) between the high- and low-intensity sessions (Δ = -30.7 ± 4.0 for the high intensity session, and Δ = -9.9 ± 2.5 for the low intensity session).CONCLUSION:The present study did not find a reduction in blood pressure after exercise in normotensive, physically active young adults. However, the measurements of the indicators of autonomic neural activity revealed that in exercise of greater intensity the parasympathetic recovery tends to be slower and that sympathetic withdrawal can apparently compensate for this delay in recovery.

Bone Marker Responses to Resistance Exercise with Vascular Restriction in Young and Older Men

Acute bouts of low intensity resistance exercise with blood flow restriction (BFR) have been shown to decrease bone resorption markers in young men. It is important to examine the influence of age on these bone marker responses. PURPOSE: To compare bone marker responses of young (n=10; 18-25 yrs) and older men (n=10; 50-64 yrs) during an acute bout of lower body resistance exercise with either a traditional (NoBFR) heavy training load (80% 1RM, 3 sets, 8 reps) or a low intensity (20% 1RM, 4 sets, 20, 15, 15, and 15 reps) session with vascular restriction (BFR). METHODS: Subjects were assigned to the two exercise sessions in a randomized, cross-over design, separated by 4 days: NoBFR or BRF for knee extension and leg press exercises. Blood samples were obtained via an indwelling venous catheter at the following time points: pre-exercise; immediate post-exercise; 15, 30, 60 min post; and 24 hours post to assess Bone-specific Alkaline Phosphatase (BAP) and C-terminal Telopeptides of Type I Collagen (CTX) using commercial ELISA kits. RESULTS: Young men had higher serum levels of both BAP (p < 0.01) and CTX (p < 0.01) at all time points compared to the older men. BAP significantly increased (p < 0.05) in response to the NoBFR protocol for both young (12% immediate post, 6% 30 min post) and older men (7% immediate post, 7% 15 min post, 4% 30 min post). The only BAP trend for the BFR protocol occurred in young men (increase from pre to immediate post, p = 0.064). There was a significant time (p < 0.05) main effect for CTX. Both resistance exercise protocols resulted in significant decreases (p < 0.01) in CTX from pre-exercise to 60 min post-exercise; however, there was a trend (p = 0.059) for the % CTX change to be greater for BFR (-20.8% ± 4.1) than NoBFR (-13.6% ± 3.7). CONCLUSION: The patterns of bone marker responses to the NoBFR and BFR protocols were similar for the young and older men. Both exercise protocols were associated with a decrease in the bone resorption marker; however, the NoBFR protocol was more effective in stimulating an increase in the bone formation marker. Our findings are consistent with previous reports that BFR decreases bone resorption markers. BAP seems to be more responsive to high intensity resistance exercise

Comparable effects of moderate intensity exercise on changes in anorectic gut hormone levels and energy intake to high intensity exercise

There is growing interest in the effects of exercise on plasma gut hormone levels and subsequent energy intake (EI) but the effects of mode and exercise intensity on anorectic hormone profiles on subsequent EI remain to be elucidated. We aimed to investigate whether circulating peptide YY(3-36) (PYY(3-36)) and glucagon-like peptide-1 (GLP-1 or GCG as listed in the HUGO Database) levels depend on exercise intensity, which could affect subsequent EI. Ten young male subjects (mean+/-s.d., age: 23.4+/-4.3 years, body mass index: 22.5+/-1.0 kg/m(2), and maximum oxygen uptake (VO(2 max)): 45.9+/-8.5 ml/kg per min) received a standardized breakfast, which was followed by constant cycling exercise at 75% VO(2 max) (high intensity session), 50% VO(2 max) (moderate intensity session), or rest (resting session) for 30 min. At lunch, a test meal was presented, and EI was calculated. Blood samples were obtained during three sessions for measurements of glucose, insulin, PYY(3-36), and GLP-1, which includes GLP-1 (7-36) amide and GLP-1 (9-36) amide. Increases in blood PYY(3-36) levels were dependent on the exercise intensity (effect of session: P<0.001 by two-way ANOVA), whereas those in GLP-1 levels were similar between two different exercise sessions. Of note, increase in area under the curve values for GLP-1 levels was negatively correlated with decrease in the EI in each exercise session (high: P<0.001, moderate: P=0.002). The present findings raise the possibility that each gut hormone exhibits its specific blood kinetics in response to two different intensities of exercise stimuli and might play differential roles in regulation of EI after exercise.

Impact Of Two Different Resistive Exercise Methods In Post-exercise Creatine-kinase Plasma Levels

PURPOSE:: The aim of this investigation was to determine the effect of two different RE methods on creatine-kinase (CK) plasma levels. METHODS: Young adult men (n= 10, 26,1± 6,3 years old; 174,0 ± 5,4 cm height; 76,4 ± 13,3 kg weight; 15,48 ± 5,42 % body fat) with previous experience in RE were divided in to two groups and both performed an exercise sessions in two different intensities determined by one maximum repetition (1MR) tests, with one week interval between them. The training sessions consisted in tree consecutive exercises for the same muscle group (bench press, incline bench press, peck deck); the variable intensity (VI) session performed 3 sets for each exercise performed at 67%, 75% and 80% of 1MR while the constant intensity (CI) group performed 3 sets for each exercise at 75% of 1MR. Blood samples were obtained from the antecubital vein at rest, immediately after, 24, 48 and 72 after the exercise sessions. CK levels were analyzed using the espectophotometry method (Bio System). Friedman-Anova was applied for analyze blood CK. Willcoxon test was utilized to detect differences. RESULTS: The results will be presented on the table bellow: CONCLUSIONS: Is well established on the literature that muscle contractions can provoke muscle damage specially 24-48 hours after the end of the exercise session. We observed an increase in CK levels 48-72 hours after the end of both exercise sessions, indicating that blood CK level may not be a good indicator of muscle damage.Table: Caption not provided.

Effect of a single session of electrical stimulation on activity and expression of citrate synthase and antioxidant enzymes in rat soleus muscle

The aim of our study was to investigate the effect of a single high intensity session of muscle contractions on the activity and expression of citrate synthase (CS) and of the following major antioxidant enzymes: Mn-superoxide dismutase (Mn-SOD), Cu,Zn-superoxide dismutase (Cu,Zn-SOD), catalase (CAT), and glutathione peroxidase (GPX). To accomplish this, soleus muscles of male Wistar rats were subjected to contractions using a intense electrical stimulation (ES) protocol. Soleus muscles were isolated either immediately or 1 h after the contractions and utilized for enzyme activity determination, and for analysis of gene expression by quantitative PCR. A significant increase in maximal activity (63%) and expression (80%) of CS was observed in stimulated soleus muscles, isolated 1 h after ES as compared to controls. However, this effect was not observed in muscles isolated immediately after ES. By using macroarray and Real Time RT-PCR analysis, an increase in expression of Mn-SOD, Cu,Zn-SOD, CAT, and GPX was also found. Interestingly, of these enzymes, only CAT activity was significantly increased (44%) 1 h after ES in soleus muscle. These results indicate that acute ES up-regulates activity and expression of CS and CAT in soleus muscles. This increase in expression of CAT may play an important role in counteracting the potential deleterious effects of elevated oxidative stress induced by a high oxidative demand in skeletal muscles subjected to exercise training.

A Comparison of Periodization Models on Rating of Perceived Exertion

Periodization is the planned manipulation of training variables in order to maximize training adaptations and prevent the onset of overtraining syndrome (OTS). It is plausible that variations in periodization could impact rating of perceived exertion (RPE) which may predispose individuals to experience OTS. PURPOSE: The aim of the present investigation was to determine if RPE differed significantly between periodization models at low (8RM), moderate (6RM), and high (4RM) training intensities. METHODS: Twenty-eight college aged men (n = 18) and women (n = 10) were randomly assigned to one of three periodization groups: linear (n = 9), daily undulating (n = 10), and weekly undulating (n = 9). Participants engaged in resistance training three days a week for nine weeks. Weekly training intensity and volume differed between groups with total volume and intensity equated for all groups over the course of the study. Before exercise training, researchers read and distributed a copy of a script to familiarize participants with the Borg C-10 scale for determining RPE. Participants indicated RPE after each of three leg press and bench press sets per training session resulting in 27 scores for each exercise at each training intensity. These scores were averaged for each individual to produce two scores: leg press RPE and bench press RPE. A one-way ANOVA was used to analyze differences in mean RPE scores across groups for each intensity level. RESULTS: No significant differences existed for leg press at low [F(2, 30) = 0.69, p = .51], moderate [F(2, 29) = 1.22, p = .31], or high [F(2, 28) = 0.78, p = .47] intensity session. Similarly, no significant differences existed for bench press at low [F(2, 30) = 0.66, p = .53, moderate [F(2, 29) = 0.09, p = .92], or high [F(2, 28) = 0.20, p = .82] intensity session. CONCLUSIONS: Examination of mean RPE scores revealed exercise was perceived to be hard regardless of periodization model and intensity level. Overall, the findings indicated periodization models do not impact perceived exertion in recreational lifters.

Hypoxic Training In Well-trained Swimmers

2311 PURPOSE: To examine the effects of hypoxia on power output and metabolism during high intensity training in a group of well trained swimmers. METHODS: 16 swimmers (10 women, 6 men) completed a 5 wk training program, consisting of three high intensity training sessions in a flume and supplemental low or moderate intensity sessions in a pool each week. Subjects were matched for gender, performance level and training history, and assigned to either hypoxic (HYPO; FIO2 = 15.3%, simulated altitude of 2500m) or normoxic (NORM; FIO2 = 20.9%) interval training in a randomized, double blind design. Each flume training session consisted of 10 bouts of 30s exercise with 15s rest, 5 bouts of 60s exercise with 30s rest and an additional 5 bouts of 30s exercise with 15s rest between each bout. Between sets rest was 2- min. During these sessions the absolute training intensity (i.e. swimming speed) was controlled by the flume operator. The relative training intensity was carefully monitored using heart rate, ventilation and oxygen uptake (VO2) measurements. Out flume training was monitored by means of individual training logs. RESULTS: Although both groups trained at similar relative intensities (see JAP: 94(2):733–43, 2003) HYPO trained at significantly (p<0.05) lower swimming speeds (2.98, 2.35 and 1.99% for training set1, 2 and 3 respectively) and thus lower power outputs (estimated (Po∼v3) 26.46, 12.98 and 7.88%) than NORM. At the metabolic level this was indicated by significantly (p<0.02) lower VO2 in the hypoxic (71.5%) compared to the normoxic group (91.8% of pre-test VO2max). Both groups significantly improved their flume training speeds (NORM: 1.5, 2.7 and 1.4% for set1, 2 and 3 respectively; HYPO: 1.0, 1.3 and 1.2%). There was no significant difference between groups for set1 and 3 (ANOVA interaction p = 0.47 and p = 0.56). NORM improved significantly more for set2 (p = 0.05). CONCLUSION: Hypoxia was unable to intensify the training stimulus and therewith enhance performance under the conditions of this experiment. Moreover, training at comparable relative intensities, the absolute power output generated by the muscle was lower in hypoxia compared to normoxia.

Breast milk composition after exercise of different intensities.

The purpose of this study was to determine if breast milk composition changed significantly following exercise conducted at different intensities. Nine postpartum women exercised on a treadmill up to maximal oxygen uptake (100% of VO2max) on the first laboratory visit, for 30 minutes on two subsequent occasions (50% and 75% of VO2max) and also performed a nonexercise control session. Blood and breast milk were collected prior to exercise, immediately after exercise, and at 30, 60, and 90 minutes postexercise. Blood samples were analyzed for lactic acid (LA) while milk samples were analyzed for LA, pH, lipid, ammonium, and urea. Milk LA after the 100% intensity session was significantly elevated through 90 minutes postexercise, while there was no significant increase in milk LA at any collection time after the 50% or 75% intensity sessions. There were no significant differences in milk pH, lipid, ammonium, or urea measurements after any of the exercise sessions. These data show that unlike maximum intensity exercise, moderate intensity exercise does not increase breast milk LA content.