Patrick L. Schneider

Validity of 10 electronic pedometers for measuring steps, distance, and energy cost.

PURPOSE This study examined the effects of walking speed on the accuracy and reliability of 10 pedometers: Yamasa Skeletone (SK), Sportline 330 (SL330) and 345 (SL345), Omron (OM), Yamax Digiwalker SW-701 (DW), Kenz Lifecorder (KZ), New Lifestyles 2000 (NL), Oregon Scientific (OR), Freestyle Pacer Pro (FR), and Walk4Life LS 2525 (WL). METHODS Ten subjects (33 +/- 12 yr) walked on a treadmill at various speeds (54, 67, 80, 94, and 107 m x min-1) for 5-min stages. Simultaneously, an investigator determined steps by a hand counter and energy expenditure (kcal) by indirect calorimetry. Each brand was measured on the right and left sides. RESULTS Correlation coefficients between right and left sides exceeded 0.81 for all pedometers except OR (0.76) and SL345 (0.57). Most pedometers underestimated steps at 54 m x min-1, but accuracy for step counting improved at faster speeds. At 80 m x min-1 and above, six models (SK, OM, DW, KZ, NL, and WL) gave mean values that were within +/- 1% of actual steps. Six pedometers displayed the distance traveled. Most of them estimated mean distance to within +/- 10% at 80 m x min-1 but overestimated distance at slower speeds and underestimated distance at faster speeds. Eight pedometers displayed kilocalories, but except for KZ and NL, it is unclear whether this should reflect net or gross kilocalories. If one assumes they display net kilocalories, the general trend was an overestimation of kilocalories at every speed. If one assumes they display gross kilocalorie, then seven of the eight pedometers were accurate to within +/-30% at all speeds. CONCLUSION In general, pedometers are most accurate for assessing steps, less accurate for assessing distance, and even less accurate for assessing kilocalories.

Accuracy and reliability of 10 pedometers for measuring steps over a 400-m walk

PURPOSE The purpose of this study was to determine the accuracy and reliability of the following electronic pedometers for measuring steps: Freestyle Pacer Pro (FR), 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), and the Yamax Digi-Walker SW-701 (DW). METHODS Ten males (34.7 +/- 12.6 yr) (mean +/- SD) and 10 females (43.1 +/- 19.9 yr) ranging in BMI from 19.8 to 33.6 kg.m-2 walked 400-m around an outdoor track while wearing two pedometers of the same model (one on the right and left sides of the body) for each of 10 models. Four pedometers of each model were assessed in this fashion. The actual steps taken were tallied by a researcher. RESULTS The KZ, NL, and DW were the most accurate in counting steps, displaying values that were within +/-3% of the actual steps taken, 95% of the time. The SL330 and OM were the least accurate, displaying values that were within +/-37% of the actual steps, 95% of the time. The reliability within a single model (Cronbachs alpha) was >0.80 for all pedometers with the exception of the SL330. The intramodel reliability was exceptionally high (>0.99) in the KZ, OM, NL, and the DW. CONCLUSION Due to the variation that exists among models in regard to the internal mechanism and sensitivity, not all pedometers count steps accurately. Thus, it is important for researchers who use pedometers to assess physical activity to be aware of their accuracy and reliability.

Effects of a 10,000 Steps per Day Goal in Overweight Adults

Purpose. This study was designed (1) to examine the effects of a 10,000 steps·d−1 exercise prescription on sedentary, overweight/obese adults, and (2) to examine the effects of adherence on body composition and cardiovascular risk factors. Methods. Fifty-six overweight/obese adults participated in the study. Body composition and cardiovascular risk factors were determined at baseline, 20 weeks, and 36 weeks. Adherence was defined as averaging ≥ 9500 steps·d−1 from week 4 to week 36. Results. 38 participants (68%) wore pedometers daily for 36 weeks and were available for posttesting. Significant improvements were noted in mean values for walking volume (3994 steps·d−1), body weight (–2.4 kg), body mass index (–0.8 kg·m−2), percentage body fat (–1.9%), fat mass (–2.7 kg), waist circumference (–1.8 cm), hip circumference (–1.9 cm) and high-density lipoprotein (3 mg/dl). The adherers had large improvements in body composition measures, whereas the nonadherers showed little or no change in these variables. Discussion. A 10,000 steps·d−1 exercise prescription resulted in weight loss over 36 weeks in previously sedentary, overweight/obese adults. Adherence to the step goal had a marked effect on the outcome.

An assessment of the total amount of physical activity of patients participating in a phase III cardiac rehabilitation program.

PURPOSE: This study was designed to assess and characterize the physical activity levels and patterns of participants in a hospital-based Phase III cardiac rehabilitation (CR) program. METHODS: Subjects consisted of 25 men with a history of coronary artery disease ranging in age from 39 to 69 years who were participating in a Phase III CR program. Physical activity in steps and energy expenditure were assessed for 7 days using an accelerometer (Actigraph GT1M). Comparisons were made between CR days and non-CR days. In addition, physical activity within and outside the CR session was also compared. RESULTS: Subjects attended CR 3.0 ± 1.0 d/wk (mean ± SD) and averaged 6,907 ± 510 steps/d (mean ± SE) over 7 days. Physical activity levels were significantly higher on CR days versus non-CR days (10,087 ± 631 vs 5,287 ± 520 steps/d). Those who performed home exercise in addition to CR were significantly more active than CR-only exercisers (7,993 ± 604 vs 5,277 ± 623 steps/d). CONCLUSIONS: These results suggest that a majority (52%) of CR participants met a minimal active goal on days they attend CR. However, only 8% reached the recommended minimum level of weekly physical activity. Those that did some form of home-exercise in addition to CR were significantly more active than the CR only exercisers. Although attending CR seems to help patients reach physical activity targets, patients should be strongly encouraged to increase their volume of physical activity either at the CR facility or at home. Activity monitors provide a practical and effective way for patients to track their physical activity levels, which may be helpful in reaching goals.

Tips for Helping Clients Meet Energy Expenditure Goals

T he majority of health/fitness professionals (HFPs) would agree that the most common client goal relates to weight loss. Although the focus of this goal from a client’s viewpoint is on pounds lost, many HFPs should think in terms of maximizing energy (caloric) expenditure in a safe, effective, and time-efficient manner. To accomplish this goal, the HFPs should have a basic understanding of the major factors that govern energy expenditure and be able to integrate these factors into the exercise prescription. The focus of this article is on individualizing the activity/exercise recommendation with the primary objective of meeting an energy expenditure goal, as it is now well accepted that health benefits from physical activity (PA) are associated with the volume of work performed. Although weight loss is among the most common goals of novice exercisers, there are other advantages to looking at energy expenditure during activity. As indicated in Table 1, the American College of Sports Medicine (ACSM) recommends a target range of 150 to 400 calories (volume of activity/exercise) of PA and/or exercise energy expenditure per day for improvements in cardiorespiratory fitness (1). The lower end of this caloric range represents a minimal physical activity energy expenditure (PAEE) threshold of about 1,000 calories per week, which is associated with a significant reduction in the risk of all-cause mortality, whereas the upper end of the range is thought to optimize health and fitness benef its. In addition, 2,000 calories per week of PAEE has been associated with a reduced risk of cardiovascular disease. With respect to weight management, ACSM guidelines indicate that at least 2,000 calories per week may be needed for both shortand long-term weight control. Regardless of the health and/or fitness-related objective, the individual’s exercise prescription should be designed with energy expenditure goals in mind (1). Edward T. Howley, Ph.D., FACSM, and colleagues (2) did a nice job of summarizing the variables that affect total energy expenditure: basal metabolic rate, thermic effect of food, and physical activity energy expenditure (PAEE). Of those factors, PAEE is the most variable and the one that can be changed daily by an individual. Physical activity energy expenditure is largely determined by the interaction between frequency, duration, and intensity. When it comes to maximizing PAEE, repetitive skeletal muscle activity is a major factor that must be considered (3). It is well known that the rate of energy expenditure is directly proportional to the intensity of the activity. Thus, for a given amount of time, more calories are burned during vigorous activity than during moderate or light intensity activities. Although intensity is a key factor affecting energy expenditure, the total amount of calories burned also depends on the amount of time the individual chooses to be physically active.