Mark Gibson

Consistency of the talk test for exercise prescription.

Implications for Muscle Lipid Metabolism and An accumulation of intramuscular lipid has been reported with obesity and linked with insulin resistance. The purpose of this paper is to discuss: 1) mechanisms that may be responsible for intramuscular lipid accumulation with obesity, and 2) the effects of common interventions (weight loss or exercise) for obesity on skeletal muscle lipid metabolism and intramuscular lipid content. Data suggest that the skeletal muscle of morbidly obese humans is characterized by the preferential partitioning of lipid toward storage rather than oxidation. This phenotype may, in part, contribute to increased lipid deposition in both muscle and adipose tissue, and promote the development of morbid obesity and insulin resistance. Weight loss intervention decreases intramuscular lipid content, which may contribute to improved insulin action. On the other hand, exercise training improves insulin action and increases fatty acid oxidation in the skeletal muscle of obese/morbidly obese individuals. In summary, the accumulation of intramuscular lipid appears to be detrimental in terms of inducing insulin resistance; however, the accumulation of lipid can be reversed with weight loss. The mechanism(s) by which exercise enhances insulin action remains to be determined.INTRODUCTION/PURPOSE The Talk Test has been shown to be well correlated with the ventilatory threshold, with accepted guidelines for exercise prescription, and with the ischemic threshold. As such, it appears to be a valuable although quite simple method of exercise prescription. In this study, we evaluate the consistency of the Talk Test by comparing responses during different modes of exercise. METHODS Healthy volunteers (N = 16) performed incremental exercise, on both treadmill and cycle ergometer. Trials were performed with respiratory gas exchange and while performing the Talk Test. Comparisons were made regarding the correspondence of the last positive, equivocal, and first negative stages of the Talk Test with ventilatory threshold. RESULTS The %VO2peak, %VO2 reserve, %HRpeak, and %HR reserve at ventilatory threshold on treadmill versus cycle ergometer (77%, 75%. 89%, and 84% vs 67%, 64%, 82%, and 74%) were not significantly different than the equivocal stage of the Talk Test (83%, 82%, 86%, and 80% vs 73%, 70%, 87%, and 81%). The VO2 at ventilatory threshold and the last positive, equivocal and negative stages of the Talk Test were well correlated during treadmill and cycle ergometer exercise. CONCLUSIONS The results support the hypothesis that the Talk Test approximates ventilatory threshold on both treadmill and cycle. At the point where speech first became difficult, exercise intensity was almost exactly equivalent to ventilatory threshold. When speech was not comfortable, exercise intensity was consistently above ventilatory threshold. These results suggest that the Talk Test may be a highly consistent method of exercise prescription.INTRODUCTION Obesity and weight gain are negative prognostic factors for breast cancer survival. Physical activity (PA) prevents weight gain and may decrease obesity. Little information exists on PA levels among cancer survivors. We assessed PA, including the proportion of breast cancer survivors engaging in recommended levels, by categories of adiposity, age, disease stage, and ethnicity in 806 women with stage 0-IIIA breast cancer participating in the Health, Eating, Activity, and Lifestyle Study. METHODS Black, non-Hispanic white, and Hispanic breast cancer survivors were recruited into the study through Surveillance Epidemiology End Results registries in New Mexico, Western Washington, and Los Angeles County, CA. Types of sports and household activities and their frequency and duration within the third yr after diagnosis were assessed during an in-person interview. RESULTS Thirty-two percent of breast cancer survivors participated in recommended levels of PA defined as 150 min x wk(-1) of moderate- to vigorous-intensity sports/recreational PA. When moderate-intensity household and gardening activities were included in the definition, 73% met the recommended level of PA. Fewer obese breast cancer survivors met the recommendation than overweight and lean breast cancer survivors (P < 0.05). Fewer black breast cancer survivors met the recommendation compared with non-Hispanic white and Hispanic breast cancer survivors (P < 0.05). CONCLUSIONS Most of the breast cancer survivors were not meeting the PA recommendations proposed for the general adult population. Efforts to encourage and facilitate PA among these women would be an important tool to decrease obesity, prevent postdiagnosis weight gain, and improve breast cancer prognosis.PURPOSE To derive a regression equation that estimates metabolic equivalent (MET) from accelerometer counts, and to define thresholds of accelerometer counts that can be used to delineate sedentary, light, moderate, and vigorous activity in adolescent girls. METHODS Seventy-four healthy 8th grade girls, age 13 - 14 yr, were recruited from urban areas of Baltimore, MD, Minneapolis/St. Paul, MN, and Columbia, SC, to participate in the study. Accelerometer and oxygen consumption (.-)VO(2)) data for 10 activities that varied in intensity from sedentary (e.g., TV watching) to vigorous (e.g., running) were collected. While performing these activities, the girls wore two accelerometers, a heart rate monitor and a Cosmed K4b2 portable metabolic unit for measurement of (.-)VO(2). A random-coefficients model was used to estimate the relationship between accelerometer counts and (.-)VO(2). Activity thresholds were defined by minimizing the false positive and false negative classifications. RESULTS The activities provided a wide range in (.-)VO(2) (3 - 36 mL x kg x min) with a correspondingly wide range in accelerometer counts (1- 3928 counts x 30 s). The regression line for MET score versus counts was MET = 2.01 +/- 0.00171 (counts x 30 s) (mixed model R = 0.84, SEE = 1.36). A threshold of 1500 counts x 30 s defined the lower end of the moderate intensity (approximately 4.6 METs) range of physical activity. That cutpoint distinguished between slow and brisk walking, and gave the lowest number of false positive and false negative classifications. The threshold ranges for sedentary, light, moderate, and vigorous physical activity were found to be 0 - 50, 51- 1499, 1500 - 2600, and >2600 counts x 30 s, respectively. CONCLUSION The developed equation and these activity thresholds can be used for prediction of MET score from accelerometer counts and participation in various intensities of physical activity in adolescent girls.

Sprint and vertical jump performances are not affected by six weeks of static hamstring stretching.

The purpose of this study was to investigate whether 6 weeks of static hamstring stretching effects range of motion (ROM), sprint, and vertical jump performances in athletes. Twenty-one healthy division III womens track and field athletes participated in the study. Subjects were tested for bilateral knee ROM; 55-m sprint time; and vertical jump height before, at 3 weeks, and after the 6-week flexibility program. Subjects were randomly assigned to treatment and control groups and warmed up with a 10-minute jog on a track before a hamstring stretching protocol. The stretching protocol consisted of four repetitions held for 45 seconds, 4 days per week. Four variables (left and right leg ROM, 55-m sprint time, vertical jump) were analyzed using a repeated-measures analysis of variance design. No significant differences (P ≤ 0.05) were found with any of the four variables between the stretching and control groups. Six weeks of a static hamstring stretching protocol did not improve knee ROM or sprint and vertical jump performances in women track and field athletes. The use of static stretching should be restricted to post practice or competition because of the detrimental effects reported throughout the literature. Based on the current investigation, it does not seem that chronic static stretching has a positive or negative impact on athletic performance. Thus, the efficacy of utilizing this practice is questionable and requires further investigation.

Translation of Submaximal Exercise Test Responses to Exercise Prescription Using the Talk Test.

Foster, C, Porcari, JP, Gibson, M, Wright, G, Greany, J, Talati, N, and Recalde, P. Translation of submaximal exercise test responses to exercise prescription using the talk test. J Strength Cond Res 23(9): 2425-2429, 2009-The exercise intensity at the Talk Test (TT) has been shown to be highly correlated with objective physiological markers, a useful outcome marker in patients with heart disease, a useful tool for avoiding exertional ischemia, and responsive to both positive and negative changes in exercise capacity. This randomized observational study evaluated the ability of the intensity at the TT during exercise testing to define absolute training workloads. Sedentary adults (n = 14) performed an incremental Balke type exercise test (3.0-3.5 mph at 0% grade, +2% grade every 2 minutes). Heart rate (HR), rating of perceived exertion (RPE), and TT were evaluated at each stage. Subsequently, the subjects performed 3 × 20-minute exercise bouts with the workload over the last 10 minutes of each bout equal to the absolute intensity at the stage preceding the LP (LP-1), at the last positive stage of the TT (LP), and at the first equivocal stage of the TT (EQ). During LP-1, LP, and EQ, HR was 140 ± 23, 151 ± 20, and 160 ± 21 bpm, or 73 ± 11, 79 ± 9, and 82 ± 9 % HRmax; RPE (CR scale) was 3.6 ± 1.5, 4.4 ± 1.8, and 6.3 ± 2.2. The TT Score-ranked as 1 = comfortable speech, 2 = slightly uncomfortable speech, and 3 = speech not comfortable-was 1.4 ± 0.5, 1.8 ± 0.4, and 2.6 ± 0.5 LP-1, LP, and at EQ, LP, respectively. The results suggest that to prescribe absolute training intensity from the TT and to get appropriate HR, RPE, and TT responses in sedentary individuals during training, the workload needs to be based on the intensity approximately 1 stage (∼1.0-1.2 metabolic equivalents) below the LP stage observed during an incremental test.

Translation of Exercise Testing to Exercise Prescription Using the Talk Test

Jeans, EA, Foster, C, Porcari, JP, Gibson, M, and Doberstein, S. Translation of exercise testing to exercise prescription using the talk test. J Strength Cond Res 25(3): 590-596, 2011-Traditionally defined in terms of %maximal heart rate (%HRmax) or %maximal metabolic equivalents, the process of exercise prescription is still difficult and individually imprecise. An alternative, and simpler, method is to define exercise intensity in terms of the Talk Test, which may be a surrogate for ventilatory threshold and more consistent with contemporary recommendations for index training intensity in well-trained and athletic individuals. This study was designed to determine how much of a reduction in the absolute exercise intensity from those observed during incremental exercise testing was necessary to allow for comfortable speech during exercise training. Fourteen well-trained (5-7 h·wk−1) individuals performed 2 incremental exercise tests (to evaluate reproducibility) and 3 steady-state training bouts (40 minutes), based on the stage before the last positive (LP) stage of the Talk Test (LP-1), the LP stage, and the equivocal (EQ) stage. The LP-1 and LP runs resulted in %HRmax and rating of perceived exertion (RPE) values within the recommended range for exercise training, the EQ run in an unacceptably high %HRmax and RPE. Most subjects could still speak comfortably during the LP-1 and LP stages, and no subject could speak comfortably during the EQ stage. The HR (r = 0.84), RPE (r = 0.81), and Talk Test (r = 0.71) responses during paired incremental tests were well correlated. The results of this test suggest that the absolute exercise intensity during the LP-1 and LP stages of incremental exercise tests with the Talk Test may produce steady-state exercise responses appropriate for training in well-trained and athletic individuals and that the reproducibility of the Talk Test is satisfactory.

The effect of handrail support on oxygen uptake during steady-state treadmill exercise.

RATIONALE Heart rate (HR) and oxygen consumption (VO(2)) are indicators of the intensity of exercise. Handrail support has been shown, during maximal treadmill testing, to blunt HR and VO(2) responses at a particular speed and grade, resulting in an increased treadmill time and overprediction in aerobic capacity. OBJECTIVES This study was designed to determine if handrail support would similarly blunt HR and VO(2) responses during steady-state treadmill exercise at intensities typical of exercise training. METHODS Healthy volunteers (age, 38-60 years; N = 10) performed maximal treadmill exercise to define VO2max (35.4 +/- 6.5 mL kg(-1) min(-1)) and ventilatory threshold (26.4 +/- 5.8 mL kg(-1) min(-1)). They also performed 3 random steady-state exercise bouts including free arm swing, handrail support-resting, and handrail support-gripping (HRS-G). Each test consisted of three 5-minute stages with intensity levels corresponding to 75%, 85%, and 95% of the speed and grade at ventilatory threshold. RESULTS There were significant (P < .05) differences in HR and VO2 at the 75%, 85%, and 95% ventilatory thresholds in HRS-G (108, 114, and 121 beats min and 17.2, 18.0, and 20.6 mL kg min, respectively) versus handrail support-resting (114, 126, and 137 beats min and 19.5, 21.8, and 23.9 mL kg min, respectively) and HRS-G versus free arm swing (120, 130, and 142 beats min and 20.3, 22.8, and 26.1 mL kg min, respectively). Rating of perceived exertion was significantly (P < .05) different between HRS-G (1.8, 2.4, and 3.1) and free arm swing (2.2, 2.9, and 3.6) at all intensities and between HRS-G (2.4 and 3.1, respectively) and handrail support-resting (3 and 3.7, respectively) at the 85% and 95% ventilatory thresholds. CONCLUSION Gripping and, to a lesser degree, resting the hands on the handrails during steady-state treadmill walking will blunt responses during exercise training and may result in less predictable exercise program.

Translation of incremental talk test responses to steady-state exercise training intensity.

PURPOSE: The Talk Test (TT) is a submaximal, incremental exercise test that has been shown to be useful in prescribing exercise training intensity. It is based on a subjects ability to speak comfortably during exercise. This study defined the amount of reduction in absolute workload intensity from an incremental exercise test using the TT to give appropriate absolute training intensity for cardiac rehabilitation patients. METHODS: Patients in an outpatient rehabilitation program (N = 30) performed an incremental exercise test with the TT given every 2-minute stage. Patients rated their speech comfort after reciting a standardized paragraph. Anything other than a “yes” response was considered the “equivocal” stage, while all preceding stages were “positive” stages. The last stage with the unequivocally positive ability to speak was the Last Positive (LP), and the preceding stages were (LP-1 and LP-2). Subsequently, three 20-minute steady-state training bouts were performed in random order at the absolute workload at the LP, LP-1, and LP-2 stages of the incremental test. Speech comfort, heart rate (HR), and rating of perceived exertion (RPE) were recorded every 5 minutes. RESULTS: The 20-minute exercise training bout was completed fully by LP (n = 19), LP-1 (n = 28), and LP-2 (n = 30). Heart rate, RPE, and speech comfort were similar through the LP-1 and LP-2 tests, but the LP stage was markedly more difficult. CONCLUSION: Steady-state exercise training intensity was easily and appropriately prescribed at intensity associated with the LP-1 and LP-2 stages of the TT. The LP stage may be too difficult for patients in a cardiac rehabilitation program.