Current limits for flowmeter resistance in metabolic carts can negatively affect exercise performance

PURPOSE

To investigate whether a metabolic cart using a flowmeter in the upper range of accepted resistance to airflow (<1.5 cmH2 O∙L-1 ∙s-1 for flows up to 14 L∙s-1 , American Thoracic Society) negatively impacts exercise performance in healthy individuals.

METHODS

16 recreationally active males (age 25 ± 1 years, height 180 ± 6 cm, weight 73.5 ± 5.8 kg, all mean ± SD) performed two incremental tests on a bicycle ergometer on each of two visits, using a metabolic cart with a flowmeter of either low (Oxycon Pro) or high (Innocor) airflow resistance. Mouth pressures, gas exchange, blood lactate concentration [La- ], perception of breathlessness, respiratory, and leg exertion were assessed throughout the tests.

RESULTS

Tests performed with the Innocor were significantly shorter (15.3 ± 3.2 vs. 15.8 ± 3.3 min, p < 0.0001) and showed higher maximal flow resistance (1.3 ± 0.2 vs. 0.3 ± 0.0 cmH2 O∙L-1 ∙s-1 , p < 0.0001). At end-exercise, peak oxygen consumption (-200 ± 220 ml.min-1 , p < 0.0001), minute ventilation (-19.9 ± 10.5 L.min-1 , p < 0.0001), breathing frequency (-5.4 ± 5.2 breaths.min-1 , p < 0.0001), heart rate (-2.1 ± 3.6 bpm, p = 0.002) and [La- ] (-0.7 ± 1.0 mmol.L-1 , p < 0.0001), but not tidal volume (-0.1 ± 0.2 L, p = 0.172) were lower with the Innocor, while the perception of breathlessness was higher (+3.8 ± 5.1 points, p < 0.0001).

CONCLUSIONS

Airflow resistance in the upper range of current guidelines can significantly affect exercise performance and respiratory pattern in young, healthy males during incremental exercise. The present results indicate the need to revisit guidelines for devices used in ergospirometry.

Validation of A New Judo-Specific Ergometer System in Male Elite and Sub-Elite Athletes

Our experimental approach included two studies to determine discriminative validity and test-retest reliability (study 1) as well as ecological validity (study 2) of a judo ergometer system while performing judo-specific movements. Sixteen elite (age: 23 ± 3 years) and 11 sub-elite (age: 16 ± 1 years) athletes participated in study 1 and 14 male sub-elite judo athletes participated in study 2. Discriminative validity and test-retest reliability of sport-specific parameters (mechanical work, maximal force) were assessed during pulling movements with and without tsukuri (kuzushi). Ecological validity of muscle activity was determined by performing pulling movements using the ergometer without tsukuri and during the same movements against an opponent. In both conditions, electromyographic activity of trunk (e.g., m. erector spinae) and upper limb muscles (e.g., m. biceps brachii) were assessed separately for the lifting and pulling arm. Elite athletes showed mostly better mechanical work, maximal force, and power (0.12 ≤ d ≤ 1.80) compared with sub-elite athletes. The receiver operating characteristic analysis revealed acceptable validity of the JERGo^© system to discriminate athletes of different performance levels predominantly during kuzushi without tsukuri (area under the curve = 0.27-0.90). Moreover, small-to-medium discriminative validity was found to detect meaningful performance changes for mechanical work and maximal force. The JERGo^© system showed small-to-high relative (ICC = 0.37-0.92) and absolute reliability (SEM = 10.8-18.8%). Finally, our analyses revealed acceptable correlations (r = 0.41-0.88) between muscle activity during kuzushi performed with the JERGo^© system compared with a judo opponent. Our findings indicate that the JERGo^© system is a valid and reliable test instrument for the assessment and training of judo-specific pulling kinetics particularly during kuzushi movement without tsukuri.

Determination of Aerobic Capacity via Cycle Ergometer Exercise Testing in Alzheimer's Disease

BACKGROUND

Older adults with Alzheimer's disease (AD) may be unable to perform treadmill testing due to balance issues. We investigated whether older adults with AD could successfully complete a peak cycle ergometer test.

METHODS

Peak oxygen consumption (peak [Formula: see text]) assessed via a cycle ergometer test in 44 participants with AD (age 78.4 ± 6.8). Physical function was assessed via the incremental shuttle walk, 6-minute walk, and the Short Physical Performance Battery (SPPB).

RESULTS

All participants completed the cycle ergometer test successfully. Peak [Formula: see text] was correlated with SPPB ( r = .35, P = .023), shuttle walk ( r = .35, P = .024), 6-minute walk ( r = .31, P = .05), and inversely with age ( r = -.4, P = .009). There was no correlation between peak [Formula: see text] and cognition.

CONCLUSION

Older adults with AD are able to safely complete a peak cycle ergometer exercise testing protocol. We provide an individualized cycle ergometer test for determining aerobic capacity in older adults with AD who may be unable to perform treadmill testing due to balance or gait issues.

[Factorial structure of physical performance in children aged of 7-8 years]

The given research is devoted to the comprehensive investigation of physical working capability within the whole range of accessible loads in healthy schoolchildren aged of 7-8 years (n=159). During the working process there were identifiedfive important facts determining the structure ofpupils ’physical working capability in the researched aged group. They include common working capability, aerobic alactant working capability, anaerobic glycolytic working capability, aerobic power and aerobic volume. The pointed out facts except the fact of common working capability, are associated with the maximum, sub maximum, large and medium zones of relative capacity respectively. During the study there were found out the expressed differences between boys and girls according to the development level of aerobic and anaerobic components ofphysical working capability. Therewith the most substantial differences were observed concerning the variables characterizing the working capability in zones of large and medium power dealing predominantly with aerobic muscle activity power supply, and the least valuable ones - in accordance with working indices in the sub maximum power dealing with anaerobic glycolytic system. The received data can be applied in solving practical problems of hygienic rating and control ofphysical loads value of different relative power during the process of physical education as well as in prenosological diagnostics of children’s health on the base of the evaluation of their organism’s adaptative capabilities.

Making Activity Recognition Robust against Deceptive Behavior

Healthcare services increasingly use the activity recognition technology to track the daily activities of individuals. In some cases, this is used to provide incentives. For example, some health insurance companies offer discount to customers who are physically active, based on the data collected from their activity tracking devices. Therefore, there is an increasing motivation for individuals to cheat, by making activity trackers detect activities that increase their benefits rather than the ones they actually do. In this study, we used a novel method to make activity recognition robust against deceptive behavior. We asked 14 subjects to attempt to trick our smartphone-based activity classifier by making it detect an activity other than the one they actually performed, for example by shaking the phone while seated to make the classifier detect walking. If they succeeded, we used their motion data to retrain the classifier, and asked them to try to trick it again. The experiment ended when subjects could no longer cheat. We found that some subjects were not able to trick the classifier at all, while others required five rounds of retraining. While classifiers trained on normal activity data predicted true activity with ~38% accuracy, training on the data gathered during the deceptive behavior increased their accuracy to ~84%. We conclude that learning the deceptive behavior of one individual helps to detect the deceptive behavior of others. Thus, we can make current activity recognition robust to deception by including deceptive activity data from a few individuals.

Time of exercise as indicator of quality control in ergometry services

BACKGROUND

The search for quality requires assessment tools in the various subdivisions of a health complex. In diagnostic medicine, they are scarce and in ergometry suggestions of indicators were not found.

OBJECTIVE

To establish indicator for quality control on ergometry based on III Guidelines of the Brazilian Cardiology Society About Ergometric Test; to verify the percentage of tests that have presented the indicator within the compliance in two services of the same institution before and after the publication of the document.

METHODS

A critical analysis of the guidelines in the search for indicator that would present: accuracy, reliability, simplicity, validity, sensitivity and ability to quantitatively measure the variations in the behavior of quality criteria and that would be applicable to all tests. The indicator was applied in tests of 2010 and 2011 prior to the publication, and after it was adopted by two services of the same institution.

RESULTS

The indicator that has met the criteria was the percentage of ergometric tests with exercise duration between 8 and 12 minutes. In the years 2010 and 2011, respectively, the percentage of ergometric tests within compliance were 85.5% and 86.1% (p=0.068) at the General Hospital, and 81.5% and 85.7% (p<0.001) the Service of Periodic Health Assessment.

CONCLUSION

The exercise time between 8 and 12 minutes can be used as a quality criterion in ergometric and services where it was applied, at least 80% of the ergometric tests were compliant.

Ergonomic status of laparoscopic urologic surgery: survey results from 241 urologic surgeons in china

Background

The prolonged and frequent use of laparoscopic equipment raises ergonomic risks that may cause physical distress for surgeons. We aimed to assess the prevalence of urologic surgeons’ physical distress associated with ergonomic problems in the operating room (OR) and their awareness of the ergonomic guidelines in China.

Methods

A sample of 300 laparoscopic urologists in China was assessed using a questionnaire on demographic information, ergonomic issues in the OR, musculoskeletal symptoms, and awareness of the ergonomic guidelines for the OR.

Results

There were 241 survey respondents (86.7%) with valid questionnaires. Among the respondents, only 43.6% placed the operating table at pubic height during the actual operation. The majority of the respondents (63.5%) used only one monitor during the procedure. Only 29.9% placed the monitor below the eye level. More than half of the respondents (50.6%) preferred to use manual control instead of the foot pedal. Most of the respondents (95.0%) never used the body support. The respondents experienced discomfort in the following regions, in ascending order: leg (21.6%), hand (30.3%), wrist (32.8%), shoulder (33.6%), back (53.1%), and neck (58.1%). The respondents with over 250 total operations experienced less discomfort than those with less than 250 total operations. Most of the respondents (84.6%) were unaware of the ergonomic guidelines. However, almost all of the respondents (98.3%) regarded the ergonomic guidelines to be important in the OR.

Conclusions

Most of the laparoscopic urologists were not aware of the ergonomic guidelines for the OR; hence, they have been suffering from varying degrees of physical discomfort caused by ergonomic issues. There is an urgent need for education regarding ergonomic guidelines in the OR for laparoscopic urologists in China.

[Pedometers for monitoring and improvement of the level of physical activity]

Pedometers are cheap and easy to handle devices that have proven their accuracy to measure the number of steps taken during a time period (day or week). However, at lower walking speeds and if used by obese persons the accuracy of several pedometers decreases significantly. Pedometers are not able to record the intensity of daily physical activity. In addition, the number of steps depends on age, gender, body weight and season. Nevertheless, monitoring of daily physical activity with a pedometer may be an effective method to enhance the daily physical activity of selected subgroups. For instance, subjects with an increased risk of obesity or hypertension, sedentary patients with diabetes mellitus type 2, patients with coronary heart disease and cancer patients can more easily be stimulated to become physically active and meet healthy living standards. Pedometers combined with existing effective counseling methods may be an effective strategy for many health care providers for adoption and enhancement of healthy lifestyles by sedentary patients.

An accurate and robust gyroscope-gased pedometer

Pedometers are known to have steps estimation issues. This is mainly attributed to their innate acceleration based measuring sensory. A micro-machined gyroscope (better immunity to acceleration) based pedometer is proposed. Through syntactic data recognition of apriori knowledge of human shank's dynamics and temporally précised detection of heel strikes permitted by Wavelet decomposition, an accurate and robust pedometer is acquired.

Devices for ambulatory and home monitoring of blood pressure, lipids, coagulation, and weight management, part 2

PURPOSE

The equipment and methods used for ambulatory and home monitoring of blood pressure, lipids, coagulation, and weight management are discussed.

SUMMARY

Over 100 million people in the United States have one or more chronic diseases, such as diabetes, hypertension, and asthma. With the goal to improve health while reducing costs and the overall health care burden, ambulatory and home monitoring by pharmacists and patients are receiving more attention. Ambulatory and home monitoring of blood pressure, cholesterol, coagulation, and weight management (including devices for assessing overweight and obese patients, heart rate monitors, and pedometers) are convenient for clinicians and patients. Such monitoring provides pharmacists with an opportunity to differentiate their practices. Studies suggest that patients who are involved in ambulatory and home monitoring take a more active role in their health and may have better adherence to a prescribed diet and medication regimens. Studies also show that ambulatory and home monitoring, if done correctly, provide clinicians with a large quantity of reliable readings for future therapeutic decisions. Devices are also a means for pharmacists to increase their provision of pharmacy services. Ambulatory monitoring is billable in many clinic settings, and the devices can be a profitable addition to prescription services.

CONCLUSION

Many devices are available to assist patients and clinicians in monitoring blood pressure, lipids, coagulation, and weight management. Familiarity with the devices will help in their proper selection and use.

Validity of the inexpensive Stepping Meter in counting steps in free living conditions: a pilot study

OBJECTIVES

To evaluate if inexpensive Stepping Meters are valid in counting steps in adults in free living conditions.

METHODS

For six days, 35 healthy volunteers wore a criterion Yamax Digiwalker and five Stepping Meters every day until all 973 pedometers had been tested. Steps were recorded daily, and the differences between counts from the Digiwalker and the Stepping Meter were expressed as a percentage of the valid value of the Digiwalker step counts. The criterion used to determine if a Stepping Meter was valid was a maximum deviation of 10% from the Digiwalker step counts.

RESULTS

A total of 252 (25.9%) Stepping Meters met the criterion, whereas 74.1% made an overestimation or underestimation of more than 10%. In more than one third (36.6%) of the invalid Stepping Meters, the deviation was greater than 50%. Most (64.8%) of the invalid pedometers overestimated the actual steps taken.

CONCLUSIONS

Inexpensive Stepping Meters cannot be used in community interventions as they will give participants the wrong message.

Moderate-to-vigorous physical activity among children: discrepancies in accelerometry-based cut-off points

OBJECTIVE

To highlight the discrepancies in accelerometry cut-off points of moderate-to-vigorous physical activity (MVPA) according to the definitions of Puyau et al. (MVPA(P)) and Trost et al. (MVPA(T)).

RESEARCH METHODS AND PROCEDURES

Forty-five children from 8 to 11 years old were monitored with the ActiGraph (ActiGraph, LLC, Fort Walton Beach, FL) for 3 consecutive days. Daily time spent at MVPA obtained with MVPA(P) was compared with that obtained with MVPA(T) using variability, regression, and agreement statistics. Data were then discussed with regard to physical activity recommendations.

RESULTS

The mean daily time spent at MVPA(P) (28 +/- 18 minutes) was significantly lower (p < 10(-4)) than that spent at MVPA(T) (141 +/- 39 minutes). The coefficient of determination between the two definitions was low (R(2) = 0.49 +/- 0.71). There was a lack of agreement between the two definitions, with a mean error or bias of 113 min/d. Thirty-four point eight percent and 100% of children underwent 30-minute MVPA/d with MVPA(P) and MVPA(T) definitions, respectively.

DISCUSSION

Comparability between studies devoted to describing children's physical activity or to assessing interventions may lack consistency according to the definition, with a real risk of misclassification.

Pedometer indices for weekly physical activity recommendations in postmenopausal women

PURPOSE

The aim of this study was to quantify pedometer-determined steps per day associated with 50, 100, and 150% of the current public health recommendation for weekly physical activity in sedentary postmenopausal women.

METHODS

A sample of 111 women from the DREW (Dose Response to Exercise in Women) study provided data. We randomly assigned women into one of three exercise groups expending 4, 8, or 12 kcal(-1).kg(-1).wk(-1) (KKW). Participants exercised alternately on a treadmill and recumbent cycle ergometer for a 6-month training period. Only treadmill sessions done with zero grade, at slow to moderate speeds (48-97 m.min(-1)) were used in this analysis. We controlled intensity at a HR equivalent to 50% of VO(2peak). Participants wore pedometers at baseline and throughout the study to assess their free-living physical activity (steps.d(-1))

RESULTS

Baseline averages were <5400 steps.d(-1) for the 4-, 8-, and 12-KKW groups. During 6 months of exercise training, free-living step counts remained <5400 steps.d(-1) and did not significantly differ from baseline for each group. Average speeds and distances per exercise session were 2.7 +/- 0.4 mph, 1.2 +/- 0.2 miles (4 KKW), 2.6 +/- 0.4 mph, 2.2 +/- 0.4 miles (8 KKW), and 2.8 +/- 0.3 mph, 2.7 +/- 0.4 miles (12 KKW). This yielded 2771 (4 KKW), 5457 (8 KKW), and 6534 (12 KKW) steps per exercise session 3-4 d.wk(-1).

CONCLUSIONS

Initially sedentary postmenopausal women can meet 50% (4 KKW), 100% (8 KKW), and 150% (12 KKW) of the current public health recommendation of weekly physical activity through planned moderate-intensity walking, accumulating an average of about 2800 (50%), 5500 (100%), and 6500 steps.d(-1) (150%) 3-4 d.wk(-1).

Validity of the ActiReg system in assessing energy requirement in chronic obstructive pulmonary disease patients

BACKGROUND & AIMS

Malnutrition and weight loss are common in patients with chronic obstructive pulmonary disease (COPD) and effective nutritional support relies on accurate assessment of energy requirement. This could only be performed by measuring energy expenditure using objective methods. The aim of this study was to examine the validity of the ActiReg system in assessing energy requirement in non-hospitalized patients with severe COPD, using doubly labelled water (DLW) as criterion method.

METHODS

Total energy expenditure (TEE) was assessed from 14 days DLW analysis in 13 patients. During the first 7 days TEE was simultaneously assessed using the ActiReg system, combining measured resting energy expenditure (REE) with physical activity monitoring.

RESULTS

A difference of -88 (782) kJ d(-1) (P = 0.69) was observed between the ActiReg system and DLW. REE explained 52% of the variation in TEE from DLW. Adding physical activity energy expenditure from the ActiReg system (PAEE(AR) = TEE(AR)-REE) increased the explained variation in TEE from DLW with 16%.

CONCLUSIONS

The ActiReg system is valid in assessing energy requirement in non-hospitalized patients with severe COPD. The unique feature of being able to discriminate within both the low intensity activity range and moderate-to-high intensity activity range makes the ActiReg system a valuable tool in clinical nutritional support.

Comparison of two waist-mounted and two ankle-mounted electronic pedometers

This study compared two ankle-mounted pedometers [StepWatch 3 (SW-3(Ankle)) and Activity Monitoring Pod 331 (AMP(Ankle))] and two waist-mounted pedometers [New Lifestyles NL-2000 (NL(Waist)) and Digiwalker SW-701 (SW-701(Waist))] under controlled and free-living conditions. In part I, 20 participants walked on a treadmill at speeds of 27-107 m min(-1). Actual steps were counted with a hand counter. In part II, participants performed leg swinging, heel tapping, stationary cycling, and car driving. In part III, 15 participants wore all pedometers for a 24 h period. The SW-3(Ankle) displayed values that were within 1% of actual steps during treadmill walking at all speeds. The other devices underestimated steps at slow speeds but all gave mean values that were within +/-3% of actual steps at 80 m min(-1) and above. The SW-3(Ankle) registered some steps during heel tapping, leg swinging, and cycling, while the AMP(Ankle) was only responsive to leg swinging. During car driving no devices recorded more than eight steps, on average. Over 24 h, the AMP(Ankle) recorded 18% fewer steps than the SW-3(Ankle) (P<0.05), while the SW-701(Waist) and the NL(Waist) recorded 15 and 11% less than the SW-3(Ankle), respectively (NSD). The SW-3(Ankle) has superior accuracy at slow treadmill walking speeds (although it was also more likely to detect "fidgeting" activities). Over 24 h, the SW-3(Ankle) tended to give higher estimates of steps per day than the other ankle- and waist-mounted pedometers.

Intermonitor variability of the RT3 accelerometer during typical physical activities

PURPOSE

To evaluate the reliability and variability of eight RT3 accelerometers.

METHODS

The RT3 were subjected to two repeated trials of six activities: rest, walking (4 and 6 km.h-1), running (8 and 10 km.h-1), and sit-stand position (20 min). One person performed all trials (female: age 24 yr, height 158.0 cm, mass 48.2 kg). Each activity lasted 12 min. The middle 10 min were taken from each 12-min trial and used as the output measure (cts.min-1). Data were analyzed for activity ( 6), monitor ( 8), and trial ( 2) effects using four three-way ANOVA: vector magnitude, X (vertical), Y (anterioposterior), and Z (mediolateral) axes.

RESULTS

Intermonitor coefficient of variation was <6% during locomotive activities, however, increased to 8-25% during sit-stand. A three-way interaction was found for vector magnitude (F35,315=88945.7, P < 0.001) and Y (F35,315=978435.6, P < 0.001) and Z axes (F35,315=103802.8, P < 0.001). A two-way activity x monitor interaction was found for the X axis (F35,315=1037787.0, P < 0.001). Follow-up tests revealed no differences between trials 1 and 2 for vector magnitude, X and Z axes. One monitor recorded significantly lower activity counts in trial 1 compared with trial 2 along the Y axis. Intermonitor differences were evident at 4, 6, 8, and 10 km.h-1 for the Y and Z axes, and at 6, 8, and 10 km.h-1 for the vector magnitude and X axis. Variability between monitors at each activity increased as intensity increased.

CONCLUSION

Reliability of the RT3 is good; however, intermonitor variability exists. The vertical axis of the RT3 accelerometer showed the least variability and was the most reliable. It is recommended that intermonitor variability and reliability of RT3 on each axis be assessed before use.

Pedometer measures of free-living physical activity: comparison of 13 models

PURPOSE

The purpose of this study was to compare the step values of multiple brands of pedometers over a 24-h period. The following 13 electronic pedometers were assessed in the study: Accusplit Alliance 1510 (AC), Freestyle Pacer Pro (FR), Colorado on the Move (CO), Kenz Lifecorder (KZ), New-Lifestyles NL-2000 (NL), Omron HJ-105 (OM), Oregon Scientific PE316CA (OR), Sportline 330 (SL330) and 345 (SL345), Walk4Life LS 2525 (WL), Yamax Skeletone EM-180 (SK), Yamax Digi-Walker SW-200 (YX200), and the Yamax Digi-Walker SW-701 (YX701).

METHODS

Ten males (39.5 +/- 16.6 yr, mean +/- SD) and 10 females (43.3 +/- 16.6 yr) ranging in BMI from 19.8 to 35.4 kg.m-2 wore two pedometers for a 24-h period. The criterion pedometer (YX200) was worn on the left side of the body, and a comparison pedometer was worn on the right. Steps counted by each device were recorded at the end of the day for each of the thirteen pedometers.

RESULTS

Subjects took an average of 9244 steps.d-1. The KZ, YX200, NL, YX701, and SL330 yielded mean values that were not significantly different from the criterion. The FR, AC, SK, CO, and SL345 significantly underestimated steps (P < 0.05) and the WL, OM, and OR significantly overestimated steps (P < 0.05) when compared with the criterion. In addition, some pedometers underestimated by 25% whereas others overestimated by 45%.

CONCLUSION

The KZ, YX200, NL, and YX701 appear to be suitable for most research purposes. Given the potential for pedometers in physical activity research, it is necessary that there be consistency across studies in the measurement of "steps per day."

Effects of body mass index on the accuracy of an electronic pedometer

Electronic pedometers are accurate for assessing steps taken while walking in normal weight adults but the accuracy of these devices has not been tested in overweight and obese men and women. The primary purpose of this study was to assess the accuracy of an electronic pedometer for measuring steps taken at various walking speeds in groups of adults with variations in body mass index (BMI). The secondary purpose was to determine if the manufacturer recommended position is the best placement position for overweight and obese adults. Participants were categorized into one of three BMI categories identified by the World Health Organization: normal (N = 25; < 25 kg x m(-2)), overweight (N = 24; 25 - 29.9 kg x m(-2)), or obese (N = 17; > or = 30 kg x m(-2)). Participants walked on a treadmill for 3 min at 54, 67, 80, 94, and 107 m x min(-1) for a total of 15 min. During the treadmill walking, three electronic pedometers tallied steps taken. The pedometers were placed at the waist level, one on the anterior mid-line of the thigh (front; manufacturer recommended placement), one on the mid-axillary line (side), and one on the posterior mid-line of the thigh (back). Concurrently, a researcher counted steps using a hand-tally counter. Category of BMI did not affect the accuracy of the pedometer at any walking speed (54 m x min(-1), p = 0.991; 67 m x min(-1), p = 0.556; 80 m x min(-1), p = 0.591; 94 m x min(-1), p = 0.426; 107 m x min(-1), p = 0.869). At 54 m x min(-1), the front, side, and back pedometers significantly underestimated hand-tally counted steps by 20 % (p < 0.001), 33 % (p < 0.001), and 26 % (p < 0.001), respectively. At 67 m x min(-1) the front, side, and back pedometers significantly underestimated hand-tally counted steps by 7 % (p = 0.027), 13 % (p < 0.001), 11 % (p = 0.002), respectively. The steps recorded by the electronic pedometers placed at the front, side and back of the waist were not significantly different than steps counted by the hand-tally counter at speeds of 80 m x min(-1) and higher for all subjects combined. An electronic pedometer accurately quantified steps walked at speeds of 80 m x min(-1) or faster in persons with a normal BMI and those classified as overweight or obese. The placement of the pedometer on the front, side or back of the waistband did not affect accuracy of the pedometer for counting steps.

Pedometer Accuracy in Nursing Home and Community-Dwelling Older Adults

PURPOSE

The accuracy of pedometers has not been thoroughly tested with older adult populations. The purpose of the present study was to examine the effects of walking speed and gait disorders on the accuracy of Yamax pedometers with nursing home residents (NH) relative to older adults living in the community.

METHODS

Pedometer accuracy was evaluated against observed steps taken during a self-paced walking test (slow, normal, and fast speeds) in 26 NH residents and 28 seniors' recreation center members (SC). Devices were attached to clothing at the waist. Walking speed was ascertained from the timed walk and a gait assessment was conducted. Percent error was calculated as ([pedometer steps - observed steps]/observed steps) x 100.

RESULTS

The walking speeds of both samples increased across self-selected paces (P < 0.0001). The community-dwelling older adults walked significantly faster (P < 0.0001) in all trials and had significantly higher (P < 0.0001) gait assessment scores (indicating fewer gait problems). Gait scores were positively associated with walking speed and pedometer percent error. Pedometers significantly underestimated NH residents' observed steps taken by 74% (slow), 55% (normal), and 46% (fast) paces (P < 0.0001). In the SC sample, the instruments failed to detect 25%, 13%, and 7% of actual steps taken, respectively (P < 0.0001). The magnitude of the error was greater for NH versus SC older adults (P < 0.0001) across all trials.

CONCLUSIONS

Slow walking speed and gait disorders hamper the utility of pedometers for physical activity measurement in frail seniors, such as NH residents, when worn at the usual attachment site. Pedometers, however, can be confidently used with ostensibly healthy older adult populations for both assessment and motivation purposes.

Validation of the MetaMax II Portable Metabolic Measurement System

The purpose of this study was to investigate the validity of the MetaMax II portable metabolic measurement system against the Douglas Bag technique. Nine recreationally active male subjects were included in a validation at 100 W, 10 well-trained male subjects at 200 W and 10 well-trained males at 250 W and at maximal exercise (volitional fatigue at a mean workload of 325 W). All testing was performed on an electronically braked bicycle at 60 rpm. At 100 W, the influence on MetaMax II measurements of adding a Douglas Bag breathing valve in series to the MetaMax II was investigated. The oxygen uptake was, for the MetaMax II, at 100 W mean 0.03 l x min (-1) higher (p < 0.01), at 200 W mean 0.02 l x min (-1) (n. s.) lower, at 250 W mean 0.04 l x min (-1) (n. s.) higher, and at 325 W mean 0.11 l x min (-1) (p < 0.05) higher. The carbon dioxide excretion was, for the MetaMax II, at 100 W mean 0.06 l x min (-1) (p < 0.01) lower, at 200 W mean 0.11 l x min (-1) (p < 0.05) lower, at 250 W mean 0.03 l x min (-1) (n. s.) lower, and at 325 W mean 0.16 l x min (-1) (p < 0.05) lower. The addition of a breathing valve in series to the MetaMax II resulted in lower breathing frequency, a higher ventilated tidal volume, and an affected gas measurement validation. In conclusion, the MetaMax II was found to be valid for metabolic gas measurements between 100 and at least 250 W.

Lower reference limit for maximal oxygen uptake in men and women

Maximal oxygen uptake (VO2max) is an important measure of exercise tolerance and low values may have clinical significance. Our purpose was to develop the necessary statistics--prediction equations and standard errors of estimate (SEE)--so that the lower reference limit for VO2max can be predicted for men and women. The subjects were healthy, non-smoking, sedentary men (n = 115) and women (n = 115) aged 20-70 years who performed 15 W min-1 cycle ergometer exercise tests. Three equations were developed for each gender using multiple linear regression with the non-exercise predictor variables of age and height, age and mass, and age and fat-free mass (FFM). The assumptions of regression analysis were examined and the predicted residual sum of squares (PRESS) method was used to cross-validate each equation. Healthy and diseased individual subject data from the literature were used to externally validate our lower reference limit statistics. The equations developed meet the assumptions of regression analysis and have an accuracy similar to the non-exercise prediction equations in the literature with R2 values of approximately 0.581. The PRESS method revealed that the equations are generalizable, i.e. may be used in future studies without a significant loss of accuracy. The lower reference limit predictions for the healthy and diseased individual subject data from the literature produced few miscategorizations unless the subjects were obese and mass was used as a predictor variable. In conclusion, the equations and SEE generated in this study can be used to predict an accurate and valid VO2max lower reference limit for a given subject.

The efficacy of ergometry determined heart rates for flatwater kayak training

The aim of this study was to investigate the use of incremental ergometry determined heart rate training intensities for the control of kayak ergometer and open water kayak training. Eight well-trained male kayakers completed a maximal incremental exercise test on an air-braked kayak ergometer for the determination of LT(1) (the power output at which blood lactate concentration increased by > or = 1 mmol x L(-1)), the associated heart rate (HR-LT(1)), VO(2)peak, maximal heart rate and maximal aerobic power. Subjects then performed 20 min trials of kayak ergometry (E), open water kayaking in a single kayak (K1) and open water kayaking in a four-seat kayak (K4) at HR-LT(1). During the three trials, heart rate was continuously measured, and blood lactate concentration, rating of perceived exertion (RPE) and stroke rate were determined every 5 min. In all trials, exercise at HR-LT(1) resulted in stable blood lactate concentrations and a stable RPE. Comparison of the three trials demonstrated that the only difference was for RPE, which was lower in (K4) than in (E), (p < 0.05). The results demonstrate that the prescription of HR-LT(1) elicits similar blood lactate concentrations during kayak ergometer and open water kayak training in both single and team boats.

Natural abundance deuterium and 18-oxygen effects on the precision of the doubly labeled water method

The doubly labeled water method for measuring total energy expenditure is subject to error from natural variations in the background 2H and 18O in body water. There is disagreement as to whether the variations in background abundances of the two stable isotopes covary and what relative doses of 2H and 18O minimize the impact of variation on the precision of the method. We have performed two studies to investigate the amount and covariance of the background variations. These were a study of urine collected weekly from eight subjects who remained in the Madison, WI locale for 6 wk and frequent urine samples from 14 subjects during round-trip travel to a locale > or = 500 miles from Madison, WI. Background variation in excess of analytical error was detected in six of the eight nontravelers, and covariance was demonstrated in four subjects. Background variation was detected in all 14 travelers, and covariance was demonstrated in 11 subjects. The median slopes of the regression lines of delta2H vs. delta18O were 6 and 7, respectively. Modeling indicated that 2H and 18O doses yielding a 6:1 ratio of final enrichments should minimize this error introduced to the doubly labeled water method.

Reliability of power in physical performance tests

The reliability of power in tests of physical performance affects the precision of assessment of athletes, patients, clients and study participants. In this meta-analytic review we identify the most reliable measures of power and the factors affecting reliability. Our measures of reliability were the typical (standard) error of measurement expressed as a coefficient of variation (CV) and the percent change in the mean between trials. We meta-analysed these measures for power or work from 101 studies of healthy adults. Measures and tests with the smallest CV in exercise of a given duration include field tests of sprint running (approximately 0.9%), peak power in an incremental test on a treadmill or cycle ergometer (approximately 0.9%), equivalent mean power in a constant-power test lasting 1 minute to 3 hours on a treadmill or cycle ergometer (0.9 to 2.0%), lactate-threshold power (approximately 1.5%), and jump height or distance (approximately 2.0%). The CV for mean power on isokinetic ergometers was relatively large (> 4%). CV were larger for nonathletes versus athletes (1.3 x), female versus male nonathletes (1.4 x), shorter (approximately 1-second) and longer (approximately 1-hour) versus 1-minute tests (< or = 1.6 x), and respiratory- versus ergometer-based measures of power (1.4 to 1.6 x). There was no clear-cut effect of time between trials. The importance of a practice trial was evident in studies with > 2 trials: the CV between the first 2 trials was 1.3 times the CV between subsequent trials; performance also improved by 1.2% between the first 2 trials but by only 0.2% between subsequent trials. These findings should help exercise practitioners and researchers select or design good measures and protocols for tests of physical performance.

Comparison of asynchronous versus synchronous arm crank ergometry

STUDY DESIGN

A direct comparison of synchronous versus asynchronous arm crank ergometry has not been carried out previously. Therefore, a comparative research design was employed.

OBJECTIVE

To assess the physiological responses of arm cranking when performed asynchronously (arms moving opposite to each other) versus synchronously (both arms moving in the same direction simultaneously).

SETTING

A university hospital setting in Galveston, Texas, USA.

METHODS

Seventeen individuals between the ages of 19 and 53 years were studied, 11 with paraplegia and six with no apparent disability. Two maximal arm crank graded exercise tests were performed with the subject seated in a wheelchair. Testing consisted of both arms (1) asynchronously (reciprocally) pushing and pulling the crank handles and (2) pushing and pulling the crank handles synchronously. Each test consisted of 2 min stages starting at 20 W and increasing 10 W per stage thereafter until exhaustion. Heart rate, oxygen consumption, and minute ventilation were measured and recorded during each stage. Blood lactate levels were monitored before and after each test. Statistical analysis was performed using the multivariate Hotelling's T2 followed by post hoc univariate tests.

RESULTS

Greater power and longer test times (both groups, P<0.05) and higher post test blood lactates (nondisabled P<0.01, paraplegic P<0.05) were achieved with asynchronous cranking versus synchronous cranking. While submaximal responses were similar between the two modes of cranking, there was a tendency for all variables to be lower with asynchronous. All subjects preferred asynchronous rather than synchronous cranking.

CONCLUSION

Despite few statistically significant differences, based on the subjective reports from all subjects, we believe there is a clinically significant difference between the two modes of cranking. The results suggest that the mode of cranking may have implications for arm crank testing, training, and functional locomotion in individuals with lower extremity impairments.

Intertester reliability of hand-held dynamometry: a concise summary of published research

Literature describing the use of hand-held dynamometry was examined to determine whether conclusions could be drawn regarding intertester reliability. 18 studies reporting intertester reliability coefficients were found and summarized. These suggest that high intertester reliability can be obtained, but that it is in jeopardy if tester strength is low relative to the forces being measured.

Identifying submaximal muscular effort: reliability of difference scores calculated from isometric and isokinetic measurements

The present investigation examined the reliability of a derived strength measurement and also how variability between test sessions affects the utility of this variable for judging an individual's muscular effort. 31 young healthy men (M age = 25 yr.) completed three isometric and isokinetic concentric contractions of the knee extensors, using maximal and self-selected submaximal efforts, on each of two test sessions. Difference scores between isometric and isokinetic measurements were calculated by subtracting the mean of the three isokinetic peak torques from the mean of the three isometric peak torques for each individual subject for maximal and submaximal efforts performed on both test sessions. For the group of subjects, difference scores were significantly greater during maximal (33 +/- 29 Nm) than submaximal (13 +/- 30 Nm) efforts, suggesting subjects could not maintain the same relationship between isometric and isokinetic muscular actions across the maximal and submaximal conditions. However, the test-retest reliability of the difference scores was only modest even when data were averaged over two test sessions (intraclass correlation coefficients were .82 for maximal, and .58 for submaximal). As a result, the range of scores within which an individual's true score might be expected to lie was large (+/- 25 Nm for maximal, and +/- 37 Nm for submaximal). Although derived strength parameters like difference scores may be effective in distinguishing submaximal from maximal efforts completed by groups of subjects, the test-retest reliability of the present scores suggests that their use in judging an individual's performance may be limited.

Internal consistency of dynamometer measurements in healthy subjects and stroke patients

Measurements of strength from six muscle groups described in two previously completed reports were analyzed further using Cronbach alpha. The coefficients were greater than .948 for a small sample of stroke patients and a larger sample of healthy individuals. This finding shows in diverse samples that the measures possess internal consistency and are measuring the same underlying construct.