Differentiated resistance training of the paravertebral muscles in patients with unstable spinal bone metastasis under concomitant radiotherapy: study protocol for a randomized pilot trial.

BACKGROUND: Metastatic bone disease is a common and severe complication in patients with advanced cancer. Radiotherapy (RT) has long been established as an effective local treatment for metastatic bone disorder. This study assesses the effects of RT combined with muscle-training exercises in patients with unstable bone metastases of the spinal column from solid tumors. The primary goal of this study is to evaluate the feasibility of muscle-training exercises concomitant to RT. Secondly, quality of life, fatigue, overall and bone survival, and local control will be assessed. METHODS/DESIGN: This study is a single-center, prospective, randomized, controlled, explorative intervention study with a parallel-group design to determine multidimensional effects of a course of exercises concomitant to RT on patients who have unstable metastases of the vertebral column, first under therapeutic instruction and subsequently performed by the patients themselves independently for strengthening the paravertebral muscles. On the days of radiation treatment the patients will be given four different types of exercises to ensure even isometric muscle training of all the spinal muscles. In the control group progressive muscle relaxation will be carried out parallel to RT. The patients will be randomized into two groups: differentiated muscle training or progressive muscle relaxation with 30 patients in each group. DISCUSSION: Despite the clinical experience that RT is an effective treatment for bone metastases, there is insufficient evidence for a positive effect of the combination with muscle-training exercises in patients with unstable bone metastases. Our previous DISPO-1 trial showed that adding muscle-training exercises to RT is feasible, whereas this was not proven in patients with an unstable spinal column. Although associated with several methodological and practical challenges, this randomized controlled trial is needed. TRIAL REGISTRATION: ClinicalTrials.gov, identifier: NCT02847754 . Registered on 27 July 2016.

Exercise and cancer: return to work as a firefighter with ostomy after rectal carcinoma - a case report.

BACKGROUND: Colorectal cancer survivors are deconditioned through anticancer therapy. Furthermore, about 10% of them have a permanent ostomy which is associated with weakened abdominal muscles and an increased risk of a hernia. This case study reports on how a firefighter with rectal carcinoma and ostomy was trained to regain operational fitness. METHODS: A 44-year-old firefighter (178 cm, 82 kg) with an adenocarcinoma of the rectum (diagnosed 24 months prior) had been treated with neoadjuvant radiochemotherapy and surgery. After 2 temporary ileostomies, a permanent colostomy was performed 14 weeks before the start of a 9-months training program. The program included sensorimotor, endurance, and strength training of increasing volume and intensity. Endurance, strength, and patient reported outcomes were assessed every 2 to 3 months. RESULTS: Training frequency varied from 1 to 3 sessions/week, although 3 to 5 sessions/week were prescribed. Peak power output was 150, 158, 167, 192, and 175 watts at baseline, 2, 4, 6, and 9 months. Maximal oxygen uptake increased from 1.56 L/min (19.0 mL/min/kg) to 2.39 L/min (28.8 mL/min/kg) after 6 months. Maximal isokinetic peak torque (MIPT) of the knee extensors were 138.0 and 196.5 Nm (Newton meter) at baseline and 6 months. MIPT of the elbow and hip flexors increased from 51.8 to 66.0 Nm and 213.8 to 239.7 Nm, respectively, after 6 months. Physical fatigue decreased by 65% and distress by about 50% after 9 months. The firefighter passed a test for occupational fitness after 6 months and was permitted to work with an exterior crew on a pump truck. CONCLUSION: It is possible for colorectal cancer survivors with ostomy to regain occupational fitness for physically demanding tasks like firefighting through an individually tailored and supervised training program.

Effects of different weight loss intervention programmes in health clubs - an observational multicenter study.

This study aimed at comparing the effectiveness of three lifestyle intervention programmes in health clubs "exercise only" (E), "exercise plus nutritional counselling" (E + NC), and "exercise plus weight loss program" (E + WLP) on weight loss under real-life conditions. An observational multicenter study including 788 overweight/obese new customers of 95 health clubs in Germany was performed. Participants chose E (n = 512, 38 ± 14 year, BMI 30.4 ± 4.7 kg/m(2)), E + NC (n = 179, 42 ± 14 year, BMI 31.7 ± 4.5 kg/m(2)), or E + WLP (n = 97, 40 ± 11 year, BMI 31.6 ± 5.1 kg/m(2)). Anthropometric data, energy expenditure, and energy intake were assessed at baseline and after 3 months. All groups significantly reduced body weight (E: -1.5 ± 2.9 kg, E + NC: -3.4 ± 3.6 kg, E + WLP: -5.5 ± 4.3 kg, p < .001 within and between groups) and body fat (E: -1.2 ± 2.4%, E + NC: -2.0 ± 2.4%, E + WLP: -3.1 ± 2.5%, p < .001 within and between groups). However, only E + WLP achieved a clinically significant weight loss of -5.9 ± 3.9%. Exercise energy expenditure increased and energy intake decreased significantly in all groups (p < .001), but to different extents. This investigation suggests that under field conditions exercise plus dietary interventions are more effective for weight loss than exercise alone. The benefits of E + WLP emphasize that interventions even performed by health clubs may elicit clinically relevant weight loss in overweight and obese new customers and can therefore be recommended.

Reliability and day-to-day variability of peak fat oxidation during treadmill ergometry.

BACKGROUND: Exercising at intensities where fat oxidation rates are high has been shown to induce metabolic benefits in recreational and health-oriented sportsmen. The exercise intensity (Fatpeak) eliciting peak fat oxidation rates is therefore of particular interest when aiming to prescribe exercise for the purpose of fat oxidation and related metabolic effects. Although running and walking are feasible and popular among the target population, no reliable protocols are available to assess Fatpeak as well as its actual velocity (VPFO) during treadmill ergometry. Our purpose was therefore, to assess the reliability and day-to-day variability of VPFO and Fatpeak during treadmill ergometry running. METHODS: Sixteen recreational athletes (f = 7, m = 9; 25 ± 3 y; 1.76 ± 0.09 m; 68.3 ± 13.7 kg; 23.1 ± 2.9 kg/m(2)) performed 2 different running protocols on 3 different days with standardized nutrition the day before testing. At day 1, peak oxygen uptake (VO2peak) and the velocities at the aerobic threshold (VLT) and respiratory exchange ratio (RER) of 1.00 (VRER) were assessed. At days 2 and 3, subjects ran an identical submaximal incremental test (Fat-peak test) composed of a 10 min warm-up (70 % VLT) followed by 5 stages of 6 min with equal increments (stage 1 = VLT, stage 5 = VRER). Breath-by-breath gas exchange data was measured continuously and used to determine fat oxidation rates. A third order polynomial function was used to identify VPFO and subsequently Fatpeak. The reproducibility and variability of variables was verified with an intraclass correlation coefficient (ICC), Pearson's correlation coefficient, coefficient of variation (CV) and the mean differences (bias) ± 95 % limits of agreement (LoA). RESULTS: ICC, Pearson's correlation and CV for VPFO and Fatpeak were 0.98, 0.97, 5.0 %; and 0.90, 0.81, 7.0 %, respectively. Bias ± 95 % LoA was -0.3 ± 0.9 km/h for VPFO and -2 ± 8 % of VO2peak for Fatpeak. CONCLUSION: In summary, relative and absolute reliability indicators for VPFO and Fatpeak were found to be excellent. The observed LoA may now serve as a basis for future training prescriptions, although fat oxidation rates at prolonged exercise bouts at this intensity still need to be investigated.

Exercise training intensity prescription in breast cancer survivors: validity of current practice and specific recommendations.

PURPOSE: Cancer survivors are recommended to perform 150 min/week of moderate or 75 min/week of vigorous aerobic exercise, but it remains unclear how moderate and vigorous intensities can be prescribed. Therefore, it was investigated whether and how intensity prescriptions for healthy adults by the American College of Sports Medicine (ACSM) need to be adapted for breast cancer survivors. METHODS: Fifty-two breast cancer survivors (stage 0-III, age 52 ± 9 years, BMI 25.4 ± 3.5 kg/m2) performed cardiopulmonary exercise tests at the end of primary therapy. Intensity classes defined as percentages of maximal heart rate (HRmax), heart rate reserve (HRR), and maximal oxygen uptake (VO2max) were compared to the ACSM's intensity classes using oxygen uptake reserve as reference. RESULTS: The prescriptions for moderate and vigorous exercise intensities were significantly different between breast cancer survivors and healthy adults when using VO2max (moderate 50-66 vs. 46-63 and vigorous 67-91 vs. 64-90% VO2max) or HRR (moderate 26-50 vs. 40-59 and vigorous 51-88 vs. 60-89 % HRR), but not when using HRmax (moderate 65-76 vs. 64-76 and vigorous 77-94 vs. 77-95% HRmax). CONCLUSIONS: In breast cancer survivors, intensity prescriptions for healthy adults result in considerably too intense training if HRR is used as guiding factor. Prescriptions using VO2max result in a slightly too low exercise intensity, whereas recommendations in percentages of HRmax appear valid. IMPLICATIONS FOR CANCER SURVIVORS: Cancer survivors should not uncritically adopt exercise intensity prescriptions for healthy adults. Specific prescriptions for the studied population are provided.

Individual response to exercise training - a statistical perspective.

In the era of personalized medicine, interindividual differences in the magnitude of response to an exercise training program (subject-by-training interaction; "individual response") have received increasing scientific interest. However, standard approaches for quantification and prediction remain to be established, probably due to the specific considerations associated with interactive effects, in particular on the individual level, compared with the prevailing investigation of main effects. Regarding the quantification of subject-by-training interaction in terms of variance components, confounding sources of variability have to be considered. Clearly, measurement error limits the accuracy of response estimates and thereby contributes to variation. This problem is of particular importance for analyses on the individual level, because a low signal-to-noise ratio may not be compensated by increasing sample size (1 case). Moreover, within-subject variation in training efficacy may contribute to gross response variability. This largely unstudied source of variation may not be disclosed by comparison to a control group but calls for repeated interventions. A second critical point concerns the prediction of response. There is little doubt that exercise training response is influenced by a multitude of determinants. Moreover, indications of interaction between influencing factors of training efficacy lead to the hypothesis that optimal predictive accuracy may be attained using an interactive rather than additive approach. Taken together, aiming at conclusive inference and optimal predictive accuracy in the investigation of subject-by-training interaction entails specific requirements that are deducibly based on statistical principles but beset with many practical difficulties. Therefore, pragmatic alternatives are warranted.

Exercise intensity classification in cancer patients undergoing allogeneic HCT.

OBJECTIVE: Exercise intervention studies during and after cancer treatment show beneficial effects for various physical and psychosocial outcomes. Current exercise intensity guidelines for cancer patients are rather general and have been adapted from American College of Sports Medicine (ACSM) recommendations for healthy individuals. Intensive cancer treatment regimens such as allogeneic hematopoietic stem cell transplantation (allo-HCT) may change the cardiovascular response to acute exercise. Therefore, we evaluated the relationships between %V˙O2 reserve (%V˙O2R, reference) and %HRR, %HRmax, and %V˙O2max and compared calculated intensities with given intensities by ACSM. METHODS: Measurements before and 180 d after allo-HCT from a randomized controlled trial were used. Only patients who reached maximal effort and at least two exercise stages in our maximal incremental cycling test were included. Before allo-HCT, 106 patients were included, and 180 d after treatment, 49 patients met our inclusion criteria. Individual regression lines were calculated with V˙O2R as the reference. Calculated exercise intensities for endurance training prescription were compared with ACSM values. RESULTS: Before allo-HCT, %HRR values of patients were significantly lower than ACSM values, and %HRmax and %V˙O2max values were significantly higher (except 90% HRmax, which was significantly lower, all P < 0.01). One hundred eighty days after allo-HCT, values for %HRR were not significantly different to ACSM values (except 90%, which was significantly lower, P = 0.01), whereas %HRmax and %V˙O2max were significantly higher (all P < 0.05). Furthermore, regression models revealed no influence of beta-blockers on calculated intensities. CONCLUSIONS: ACSM's exercise intensity recommendations for endurance training may not be applicable for cancer patients during and 180 d after allo-HCT because they may not meet the targeted intensity class, with the exception of %HRR 180 d after allo-HCT.

Cardiorespiratory fitness in breast cancer patients undergoing adjuvant therapy.

PURPOSE: The aim of this work was to investigate cardiorespiratory fitness in breast cancer patients at different time points of anti-cancer treatment. PATIENTS AND METHODS: Non-metastatic breast cancer patients (n = 222, mean age 55 years) were categorized into four subgroups according to their treatment status. Cardiopulmonary exercise testing (CPET) was used to measure patients' cardiorespiratory fitness, including oxygen delivery and metabolic muscle function. Testing was performed by bicycle ergometry, and maximal oxygen uptake (VO2peak) was measured. Heart rate during exercise at 50 watts (HR50) was assessed as a cardiocirculatory parameter and ventilatory threshold (VT) was used as an indicator of the O2 supply to muscle. Analysis of covariance was used to estimate the impact of different cancer treatments on cardiorespiratory fitness with adjustment for clinical factors. RESULTS: Submaximal measures were successfully assessed in 220 (99%) and 200 (90%) patients for HR50 and VT, while criteria for maximal exercise testing were met by 176 patients (79%), respectively. The mean VO2peak was 20.6 ± 6.7 ml/kg/min, mean VT 10.7 ± 2.9 ml/min/kg and mean HR50 112 ± 16 beats/min. Chemotherapy was significantly associated with decreased VO2peak, with significantly lower adjusted mean VO2peak among patients post adjuvant chemotherapy compared to patients with no chemotherapy or those who just started chemotherapy regime (all p < 0.01). Patients post adjuvant chemotherapy reached only 63% of the VO2peak level expected for their age- and BMI-category (mean VO2peak 15.5 ± 4.8 ml/kg/min). Similarly, HR50 was significantly associated with treatment. However, VT was not associated with treatment. CONCLUSION: Breast cancer patients have marked and significantly impaired cardiopulmonary function during and after chemotherapy. Hereby, chemotherapy appears to impair cardiorespiratory fitness by influencing the oxygen delivery system rather than impacting metabolic muscle function. Our findings underline the need of exercise training in breast cancer patients to counteract the loss of cardiorespiratory fitness during the anti-cancer treatment.

Irisin does not mediate resistance training-induced alterations in resting metabolic rate.

PURPOSE: This study aimed to investigate the effects of a 6-month preventive resistance training program on resting metabolic rate (RMR) and its associations with fat-free mass (FFM) and the newly described myokine irisin as two potential mechanistic links between exercise training and RMR. METHODS: In a randomized controlled trial, 74 sedentary healthy male and female participants either completed 6 months of high-repetition resistance training 3 d·wk in accordance with the American College of Sports Medicine recommendations (RT: n = 37; 47 ± 7 yr; body mass index, 25.0 ± 3.4 kg·m) or served as controls (CO: n = 37; 50 ± 7 yr; body mass index, 24.2 ± 3.2 kg·m). Strength (one-repetition maximum), RMR (indirect calorimetry), body fat (caliper method), and serum irisin concentration (enzyme-linked immunosorbent assay) were measured before and after 6 months of training. RESULTS: Training led to an increase in strength (one-repetition maximum leg press, 16% ± 7%; P < 0.001). RMR increased in RT (1671 ± 356 vs 1843 ± 385 kcal·d, P < 0.001) but not in CO (1587 ± 285 vs 1602 ± 294 kcal·d, P = 0.97; group-time interaction, P < 0.01). Body weight (RT, -0.5 ± 2.4 kg; CO, 0.1 ± 2.3 kg), body fat percentage (RT, -1.1% ± 2.5%; CO, -0.7% ± 2.9%), and FFM (RT, 0.4 ± 2.1 kg; CO, 0.6 ± 1.9 kg) did not develop differently between groups (group-time interaction: P = 0.29, P = 0.54, and P = 0.59, respectively). Serum irisin concentration increased in CO (70.8 ± 83.4 ng·mL, P < 0.001) but not in RT (22.4 ± 92.6 ng·mL, P = 0.67; group-time interaction, P < 0.01). The change in RMR was not associated with the change in FFM (r = -0.11, P = 0.36) or irisin (r = -0.004, P = 0.97). CONCLUSIONS: Preventive resistance training elicits an increase in RMR. However, in contrast to currently discussed hypotheses, this increase does not seem to be mediated by training-induced changes in FFM or circulating irisin concentration, which casts doubt in the meaning of irisin for human energy balance.

Can more than one incremental cycling test be performed within one day?

Changes in performance parameters over four consecutive maximal incremental cycling tests were investigated to determine how many tests can be performed within one single day without negatively affecting performance. Sixteen male and female subjects (eight trained (T): 25 ± 3 yr, BMI 22.6 ± 2.5 kg·m(-2), maximal power output (P(max)) 4.6 ± 0.5 W·kg(-1); eight untrained (UT): 27 ± 3 yr, BMI 22.3 ± 1.2 kg·m(-2), P(max) 2.9 ± 0.3 W·kg(-1)) performed four successive maximal incremental cycling tests separated by 1.5 h of passive rest. Individual energy requirements were covered by standardised meals between trials. Maximal oxygen uptake (VO(2max)) remained unchanged over the four tests in both groups (P = 0.20 and P = 0.33, respectively). P(max) did not change in the T group (P = 0.32), but decreased from the third test in the UT group (P < 0.01). Heart rate responses to submaximal exercise were elevated from the third test in the T group and from the second test in the UT group (P < 0.05). The increase in blood lactate shifted rightward over the four tests in both groups (P < 0.001 and P < 0.01, respectively). Exercise-induced net increases in epinephrine and norepinephrine were not different between the tests in either group (P ≥ 0.15). If VO(2max) is the main parameter of interest, trained and untrained individuals can perform at least four maximal incremental cycling tests per day. However, because other parameters changed after the first and second test, respectively, no more than one test per day should be performed if parameters other than VO(2max) are the prime focus.

Medical results of preparticipation examination in adolescent athletes.

BACKGROUND: Preparticipation examinations (PPE) are frequently used to evaluate eligibility for competitive sports in adolescent athletes. Nevertheless, the effectiveness of these examinations is under debate since costs are high and its validity is discussed controversial. PURPOSE: To analyse medical findings and consequences in adolescent athletes prior to admission to a sports school. METHODS: In 733 adolescent athletes (318 girls, 415 boys, age 12.3±0.4, 16 sports disciplines), history and clinical examination (musculoskeletal, cardiovascular, general medicine) was performed to evaluate eligibility. PPE was completed by determination of blood parameters, ECG at rest and during ergometry, echocardiography and x-rays and ultrasonography if indicated. Eligibility was either approved or rated with restriction. Recommendations for therapy and/or prevention were given to the athletes and their parents. Results Historical (h) and clinical (c) findings (eg, pain, verified pathologies) were more frequent regarding the musculoskeletal system (h:120, 16.4%; c:247, 33.7%) compared to cardiovascular (h:9, 1.2%; c:23, 3.1%) or general medicine findings (h:116, 15.8%; c:71, 9.7%). ECG at rest was moderately abnormal in 46 (6.3%) and severely abnormal in 25 athletes (3.4%). Exercise ECG was suspicious in 25 athletes (3.4%). Relevant echocardiographic abnormalities were found in 17 athletes (2.3%). In 52 of 358 cases (14.5%), x-rays led to diagnosis (eg, Spondylolisthesis). Eligibility was temporarily restricted in 41 athletes (5.6%). Three athletes (0.4%) had to be excluded from competitive sports. Therapy (eg, physiotherapy, medication) and/or prevention (sensorimotor training, vaccination) recommendations were deduced due to musculoskeletal (t:n=76,10.3%;p: n=71,9.8%) and general medicine findings (t:n=80, 10.9%; p:n=104, 14.1%). CONCLUSION: Eligibility for competitive sports is restricted in only 5.5% of adolescent athletes at age 12. Eligibility refusals are rare. However, recommendations for therapy and prevention are frequent, mainly regarding the musculoskeletal system. In spite of time and cost consumption, adolescent preparticipation before entering a career in high-performance sports is supported.

Resting metabolic rate in elite rowers and canoeists: difference between indirect calorimetry and prediction.

BACKGROUND: Athletes may differ in their resting metabolic rate (RMR) from the general population. However, to estimate the RMR in athletes, prediction equations that have not been validated in athletes are often used. The purpose of this study was therefore to verify the applicability of commonly used RMR predictions for use in athletes. METHODS: The RMR was measured by indirect calorimetry in 17 highly trained rowers and canoeists of the German national teams (BMI 24 ± 2 kg/m(2), fat-free mass 69 ± 15 kg). In addition, the RMR was predicted using Cunningham (CUN) and Harris-Benedict (HB) equations. A two-way repeated measures ANOVA was calculated to test for differences between predicted and measured RMR (α = 0.05). The root mean square percentage error (RMSPE) was calculated and the Bland-Altman procedure was used to quantify the bias for each prediction. RESULTS: Prediction equations significantly underestimated the RMR in males (p < 0.001). The RMSPE was calculated to be 18.4% (CUN) and 20.9% (HB) in the entire group. The bias was 133 kcal/24 h for CUN and 202 kcal/24 h for HB. CONCLUSIONS: Predictions significantly underestimate the RMR in male heavyweight endurance athletes but not in females. In athletes with a high fat-free mass, prediction equations might therefore not be applicable to estimate energy requirements. Instead, measurement of the resting energy expenditure or specific prediction equations might be needed for the individual heavyweight athlete.

The intensity and effects of strength training in the elderly.

BACKGROUND: The elderly need strength training more and more as they grow older to stay mobile for their everyday activities. The goal of training is to reduce the loss of muscle mass and the resulting loss of motor function. The dose-response relationship of training intensity to training effect has not yet been fully elucidated. METHODS: PubMed was selectively searched for articles that appeared in the past 5 years about the effects and dose-response relationship of strength training in the elderly. RESULTS: Strength training in the elderly (>60 years) increases muscle strength by increasing muscle mass, and by improving the recruitment of motor units, and increasing their firing rate. Muscle mass can be increased through training at an intensity corresponding to 60% to 85% of the individual maximum voluntary strength. Improving the rate of force development requires training at a higher intensity (above 85%), in the elderly just as in younger persons. It is now recommended that healthy old people should train 3 or 4 times weekly for the best results; persons with poor performance at the outset can achieve improvement even with less frequent training. Side effects are rare. CONCLUSION: Progressive strength training in the elderly is efficient, even with higher intensities, to reduce sarcopenia, and to retain motor function.

Physical activity levels to estimate the energy requirement of adolescent athletes.

Adequate energy intake in adolescent athletes is considered important. Total energy expenditure (TEE) can be calculated from resting energy expenditure (REE) and physical activity level (PAL). However, validated PAL recommendations are available for adult athletes only. Purpose was to comprise physical activity data in adolescent athletes and to establish PAL recommendations for this population. In 64 competitive athletes (15.3 ± 1.5 yr, 20.5 ± 2.0 kg/m2) and 14 controls (15.1 ± 1.1 yr, 21 ± 2.1 kg/m2) TEE was calculated using 7-day activity protocols validated against doubly-labeled water. REE was estimated by Schofield-HW equation, and PAL was calculated as TEE:REE. Observed PAL in adolescent athletes (1.90 ± 0.35) did not differ compared with controls (1.84 ± 0.32, p = .582) and was lower than recommended for adult athletes by the WHO. In conclusion, applicability of PAL values recommended for adult athletes to estimate energy requirements in adolescent athletes must be questioned. Instead, a PAL range of 1.75-2.05 is suggested.

How to test maximal oxygen uptake: a study on timing and testing procedure of a supramaximal verification test.

Verification tests are becoming increasingly common for confirming maximal oxygen uptake (VO2 max) attainment. Yet, timing and testing procedures vary between working groups. The aims of this study were to investigate whether verification tests can be performed after an incremental test or should be performed on a separate day, and whether VO2 max can still be determined within the first testing session in subjects not satisfying the verification criterion. Forty subjects (age, 24 ± 4 years; VO2 max, 50 ± 7 mL·min-1·kg-1) performed a maximal incremental treadmill test and, 10 min afterwards, a verification test (VerifDay1) at 110% of maximal velocity (vmax). The verification criterion was a VerifDay1 peak oxygen uptake (VO2 peak) ≤5.5% higher than the incremental test value. Subjects not achieving the verification criterion performed another verification test at 115% vmax (VerifDay1') 10 min later, trying to confirm VerifDay1 VO2 peak as VO2 max. All other subjects exclusively repeated VerifDay1 on a separate day (VerifDay2). Of the 40 subjects, 6 did not satisfy the verification criterion. In 4 of them, attainment of VO2 max was confirmed by VerifDay1'. VO2 peak was equivalent between VerifDay1 and VerifDay2 (3722 ± 991 mL·min-1 vs. 3752 ± 995 mL·min-1, p = 0.56), whereas time to exhaustion was significantly longer in VerifDay2 (2:06 ± 0:22 min:s vs. 2:42 ± 0:38 min:s, p < 0.001, n = 34). The verification test VO2 peak does not seem to be affected by a preceding maximal incremental test. Incremental and verification tests can therefore be performed within the same testing session. In individuals not achieving the verification criterion, VO2 max can be determined by means of a subsequent, more intense verification test in most but not all cases.

Exercise at given percentages of VO2max: heterogeneous metabolic responses between individuals.

PURPOSE: Given percentages of VO(2max) are widely used for training and study purposes although they might not result in homogeneous metabolic strain. Therefore, the homogeneity of metabolic responses to prolonged exercise at fixed percentages of VO(2max) should be investigated. PROCEDURES: Twenty-one healthy male subjects (29+/-5 years, 77+/-8 kg, VO(2max): 59.9+/-11.8 ml min(-1)kg(-1)) performed two incremental tests to exhaustion on a cycle ergometer to determine VO(2max). Subsequently, two 60 min tests at 60 and 75% VO(2max) were conducted in randomised order. VO(2) was kept constant by adjusting the work rate. Blood lactate (La) responses as primary outcome variable to quantify metabolic strain were assessed. FINDINGS: Mean La was 2.1+/-1.1 mmol l(-1) (min-max: 0.7-5.6 mmol l(-1)) during the 60% VO(2max) test and 4.6+/-1.9 mmol l(-1) (min-max: 2.2-8.0 mmol l(-1)) during the 75% VO(2max) test. The coefficients of variation of La amounted for 52.4 and 41.3% during the 60 and 75% VO(2max) test, respectively. La responses did not differ significantly between three subgroups of the subjects (N=7 with VO(2max)<55 ml min(-1)kg(-1), N=7 with VO(2max) 55-65 ml min(-1)kg(-1), and N=7 with VO(2 max)>65 ml min(-1)kg(-1); P>or=0.08). CONCLUSION: Altogether, prolonged exercise at given percentages of VO(2max) leads to inhomogeneous metabolic strain as indicated by the large variability of La responses. This holds true even in subgroups of similar aerobic capacity. Thus, intensity prescription for endurance training and study purposes should not be solely based upon percentages of VO(2max) when a comparable metabolic strain is intended.

Time course of changes in endurance capacity: a 1-yr training study.

PURPOSE: To investigate the magnitude and the time course of changes in endurance capacity during the first year of an aerobic endurance training program with constant HR prescription. METHODS: Eighteen previously untrained subjects (7 males and 11 females, 42 +/- 5 yr, BMI of 24.3 +/- 2.5 kg x m(-2), and maximal oxygen uptake (VO(2max)) of 37.7 +/- 4.6 mL x min(-1) x kg(-1)) completed a 12-month jogging/walking program on 3 d x wk(-1) 45 min per session with a constant HR prescription of 60% HR reserve. Exhaustive treadmill tests were conducted before the intervention and after 3, 6, 9, and 12 months of training. In addition, submaximal tests on an indoor running track were performed every 4 wk. RESULTS: After 12 months, VO(2max) had increased by 0.36 +/- 0.33 L x min(-1) (median [interquartile range]: 16% [9%-20%], P < 0.001). After 3, 6, and 9 months, 52%, 65%, and 79% of this increase were reached, respectively. Resting HR decreased by a total of 9 +/- 6 min(-1) (P<0.001). Of this change, 47% and 102% had occurred after 3 and 6 months, respectively. Submaximal exercise HR during the treadmill tests decreased by 11 +/- 7 min(-1) (P < 0.001) on average. After 3 and 6 months of training, 93% and 101% of this change were observed, respectively. The running track tests revealed that submaximal exercise HR did not change significantly after the ninth week of training. CONCLUSIONS: Beginners in recreational endurance exercise are advised to increase their training stimulus after 6 months of training to maintain training effectiveness because no further significant changes in endurance capacity were observed thereafter. When planning future endurance training studies in untrained subjects, it should be taken into account that submaximal exercise HR might reflect endurance changes during the first week only, whereas VO(2max) remains responsive after several months.