Murat Karabulut

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

PURPOSEnThis 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).nnnMETHODSnTen 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.nnnRESULTSnCorrelation 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.nnnCONCLUSIONnIn general, pedometers are most accurate for assessing steps, less accurate for assessing distance, and even less accurate for assessing kilocalories.

The effects of low-intensity resistance training with vascular restriction on leg muscle strength in older men

The purpose of this study was to investigate and compare the effects of two types of resistance training protocols on the adaptation of skeletal muscle strength in older men. Thirty-seven healthy male subjects (50–64xa0years) participated in this study. Subjects were assigned to one of three groups: high-intensity (80% 1-RM) resistance training (RT80); low-intensity (20% 1-RM) resistance training with vascular restriction (VR-RT20); and a control group (CON) that performed no exercise. Subjects in both exercise groups performed three upper body (at 80% 1-RM) and two lower body exercises either with (20% 1-RM) or without (80% 1-RM) vascular restriction three times a week for 6xa0weeks. As expected, the RT80 and VR-RT20 groups had significantly (pxa0<xa00.01) greater strength increases in all upper body and leg press exercises compared with CON, however, absolute strength gains for the RT80 and VR-RT20 groups were similar (pxa0>xa00.05). It should be noted that the percentage increase in leg extension strength for the RT80 group was significantly greater than that for both the VR-RT20 (pxa0<xa00.05) and CON groups (pxa0<xa00.01), while the percentage increase in leg extension strength for the VR-RT20 group was significantly (pxa0<xa00.01) greater than that for the CON. The findings suggested that leg muscle strength improves with the low-load vascular restriction training and the VR-RT20 training protocol was almost as effective as the RT80 training protocol for increasing muscular strength in older men.

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

This study compared two ankle-mounted pedometers [StepWatch 3 (SW-3Ankle) and Activity Monitoring Pod 331 (AMPAnkle)] and two waist-mounted pedometers [New Lifestyles NL-2000 (NLWaist) and Digiwalker SW-701 (SW-701Waist)] under controlled and free-living conditions. In part I, 20 participants walked on a treadmill at speeds of 27–107xa0mxa0min−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 24xa0h period. The SW-3Ankle 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 80xa0mxa0min−1 and above. The SW-3Ankle registered some steps during heel tapping, leg swinging, and cycling, while the AMPAnkle was only responsive to leg swinging. During car driving no devices recorded more than eight steps, on average. Over 24xa0h, the AMPAnkle recorded 18% fewer steps than the SW-3Ankle (P<0.05), while the SW-701Waist and the NLWaist recorded 15 and 11% less than the SW-3Ankle, respectively (NSD). The SW-3Ankle has superior accuracy at slow treadmill walking speeds (although it was also more likely to detect “fidgeting” activities). Over 24xa0h, the SW-3Ankle tended to give higher estimates of steps per day than the other ankle- and waist-mounted pedometers.

Effects of high-intensity resistance training and low-intensity resistance training with vascular restriction on bone markers in older men

The aim of this study was to examine and compare the effects of different resistance training protocols on bone marker concentrations in older men. Thirty-seven healthy older male subjects were assigned to one of three groups: high-intensity resistance training (HI-RT, agexa0=xa057.5xa0±xa00.8); low-intensity resistance training with vascular restriction (LI-VRT, agexa0=xa059.9xa0±xa01.0); and control (CON, agexa0=xa057.0xa0±xa01.1). Blood samples were collected before and after 6xa0weeks of resistance training to measure the changes in bone formation [bone alkaline phosphatase, (Bone ALP)] and resorption (C-terminal cross-linking telopeptide of Type-I collagen, CTX) marker concentrations. A significant main effect for time was detected in Bone ALP to CTX ratio for the exercise groups (pxa0<xa00.05). There was a significant group effect for percentage changes in serum Bone ALP (21% for LI-VRT, 23% for HI-RT, and 4.7% for CON) and post hoc analysis identified significant increases in serum Bone ALP concentrations in LI-VRT (pxa0=xa00.03) and HI-RT (pxa0=xa00.02) when compared with CON. The exercise groups had significantly (pxa0<xa00.01) greater strength increases in all upper body and leg exercises compared with CON with no significant differences between the exercise groups except for leg extension strength (HI-RTxa0>xa0LI-VRT, pxa0<xa00.05). Serum concentrations of Bone ALP and Bone ALP to CTX ratio improved in both resistance training protocols, suggesting increased bone turnover with a balance favoring bone formation. Therefore, despite using low mechanical load, LI-VRT is a potentially effective training alternative to traditional HI-RT for enhancing bone health in older men.

The effects of different initial restrictive pressures used to reduce blood flow and thigh composition on tissue oxygenation of the quadriceps

Abstract Blood flow restriction training technique can be affected by several factors resulting in changes in responses to training; therefore it is necessary to investigate and reveal detailed information about this novel training technique. Participants had their thigh size, thickness of subcutaneous fat, and regional bone free muscle mass measured prior to testing. A Near-Infrared Spectrometer was used to measure tissue oxygenation and a cardiovascular profiling system was utilised to measure stroke volume and heart rate. Initial restrictive pressure of 30, 50, and 70 mmHg were set in random order on three separate days, and then six target pressures were sequentially applied. Tissue oxygenation decreased significantly as both initial restrictive pressure and target pressures increased, but the magnitude of decreases was stronger with higher initial restrictive pressure. There were significant negative correlations between tissue oxygenation and leg lean body mass, total lean body mass, and thigh circumference when initial restrictive pressure was set at 30 mmHg. The findings indicated that changes in initial restrictive pressure affected the amount of venous return verified by the decreases in tissue oxygenation and stroke volume. In addition, thigh composition and size had a significant impact on the effects of initial restrictive pressure.

Neuromuscular fatigue following low-intensity dynamic exercise with externally applied vascular restriction

This study investigated neuromuscular fatigue following low-intensity resistance exercise with vascular restriction (VR) and without vascular restriction (control, CON). Fourteen males participated in two experimental trials (VR and CON) each separated by 48 h. Each participant performed two isometric maximum voluntary contractions (MVCs) before and after five sets of 20 dynamic constant external resistance leg extension exercises (DCER-EX) at 20% of one-repetition maximum (1-RM). The participants were asked to lift (1.5s) and lower (1.5s) the load at a constant velocity. Surface electromyography (EMG) was recorded from the vastus lateralis during MVC and DCER-EX. Twitch interpolation was used to assess the percent of maximal voluntary activation (%VA) during the MVC. During performing five sets of 20 DCER-EX, the increases (p<0.05) in EMG amplitude and decreases (p<0.05) in EMG mean power frequency were similar for both VR and CON. However, there were significant differences between VR and CON for MVC force, %VA, and potentiated twitch force and significant interactions for EMG amplitude. VR decreased MVC force, %VA, potentiated twitch force, and EMG amplitude more than CON. Our findings suggest that the VR-induced fatigue may have been due to a combination of peripheral (decreases in potentiated twitch) and central (decreases in %VA and EMG amplitude) fatigue.

Percent body fat estimations in college women using field and laboratory methods: a three-compartment model approach

BackgroundMethods used to estimate percent body fat can be classified as a laboratory or field technique. However, the validity of these methods compared to multiple-compartment models has not been fully established. This investigation sought to determine the validity of field and laboratory methods for estimating percent fat (%fat) in healthy college-age women compared to the Siri three-compartment model (3C).MethodsThirty Caucasian women (21.1 ± 1.5 yrs; 164.8 ± 4.7 cm; 61.2 ± 6.8 kg) had their %fat estimated by BIA using the BodyGram™ computer program (BIA-AK) and population-specific equation (BIA-Lohman), NIR (Futrex® 6100/XL), a quadratic (SF3JPW) and linear (SF3WB) skinfold equation, air-displacement plethysmography (BP), and hydrostatic weighing (HW).ResultsAll methods produced acceptable total error (TE) values compared to the 3C model. Both laboratory methods produced similar TE values (HW, TE = 2.4%fat; BP, TE = 2.3%fat) when compared to the 3C model, though a significant constant error (CE) was detected for HW (1.5%fat, p ≤ 0.006). The field methods produced acceptable TE values ranging from 1.8 – 3.8 %fat. BIA-AK (TE = 1.8%fat) yielded the lowest TE among the field methods, while BIA-Lohman (TE = 2.1%fat) and NIR (TE = 2.7%fat) produced lower TE values than both skinfold equations (TE > 2.7%fat) compared to the 3C model. Additionally, the SF3JPW %fat estimation equation resulted in a significant CE (2.6%fat, p ≤ 0.007).ConclusionData suggest that the BP and HW are valid laboratory methods when compared to the 3C model to estimate %fat in college-age Caucasian women. When the use of a laboratory method is not feasible, NIR, BIA-AK, BIA-Lohman, SF3JPW, and SF3WB are acceptable field methods to estimate %fat in this population.

Inflammation marker, damage marker and anabolic hormone responses to resistance training with vascular restriction in older males.

The goal of this study was to examine anabolic hormone, muscle damage marker and inflammation marker responses to two types of resistance training protocols in older men. Thirty‐six healthy older males (mean age = 56·6 ± 0·6 years) completed 6 weeks of high‐intensity resistance training (HI‐RT), low‐intensity resistance training with vascular restriction (LI‐BFR) or no exercise control group (CON) three times per week. Three upper body exercises were performed by both exercise groups at the same intensity (at 80% 1‐RM), but lower body exercises were performed by the HI‐RT group at 80% 1‐RM and by the LI‐BFR group at 20% 1‐RM with vascular restriction. Resting serum creatine kinase (CK), interleukin 6 (IL‐6), insulin‐like growth factor‐I (IGF‐I), IGF binding protein 3 (IGFBP‐3) and testosterone (T) were measured before and after training. No significant group differences in resting CK, IL‐6, IGF‐I, IGFBP‐3 and T were detected following training (P>0·05). In addition, there were no significant changes in muscle cross‐sectional area (CSA), but a trend for significant decreases in the percent changes in thigh subcutaneous fat (P = 0·051). Although training‐induced anabolic hormone response did not reach statistical significance, our findings on CK and IL‐6 indicated that the LI‐BFR training protocol was safe and well tolerated for older men to perform to improve muscular strength.

Tissue oxygenation, strength and lactate response to different blood flow restrictive pressures.

This study aimed to determine whether changes in initial restrictive pressures (IRP, tightness of the cuff before inflation with air) affect tissue oxygenation, lactate production and leg strength before, during and after knee extension exercises. The cuff was positioned on the right thigh, and the IRP of either 40–45 or 60–65 mmHg were applied randomly prior to inflating the cuff to the final restrictive pressure (the pressure reached after inflating the cuff with air). Subjects performed four sets (30, 15, 15 and 15 reps) of isotonic knee extensions with 1‐min rest between sets. Tissue oxygenation and blood lactate levels were assessed prior to, during and after exercise, and leg strength was assessed pre‐ and postexercise. There were significant condition by time interactions (P<0·01) and main effects for both condition (P<0·01) and time (P<0·01) for tissue oxygenation, deoxyhaemoglobin, total haemoglobin. Significant main effects were detected for both condition (P<0·01) and time (P<0·01) for leg strength values. There was only a significant time main effect for lactate concentrations. This study is the first to show that a higher IRP had a significant impact on percent tissue oxygenation, leg strength and deoxygenated haemoglobin accumulation during exercise.

Neuromuscular response to varying pressures created by tightness of restriction cuff

Variation in regional body composition between genders may change the degree of pressure created by the tightness of cuff used during blood flow restriction training resulting in changes in the level of neuromuscular activation. This study investigates the effects of tightness of cuff and skin and subcutaneous fat thickness on electromyography (EMG) amplitude (RMS) and median frequency (MDF) during exercises and strength testing. Subjects performed knee-extension exercises with varying tightness of cuff while using EMG to measure changes in neuromuscular response. EMG RMS was significantly affected by tightness of cuff and skin and subcutaneous fat thickness. The strongest individual variable for the changes in MDF was also skin and subcutaneous-fat thickness. The changes in EMG response due to tightness of cuff and the effect of skin and subcutaneous fat thickness on tightness of cuff prove the importance of details on BFR protocol and leg composition on neuromuscular function during BFR exercises.