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The purpose of this study was to determine whether applying "varied" versus constant pelvis assistance force mediolaterally toward the paretic side of stroke survivors during walking would result in short-term improvement in weight shift toward the paretic side. Twelve individuals post-stroke (60.4 ± 6.2 years; gait speed: 0.53 ± 0.19 m/s) were tested under two conditions (varied vs. constant). Each condition was conducted in a single separate session, which consisted of (a) treadmill walking with no assistance force for 1 min (baseline), pelvis assistance toward the paretic side for 9 min (adaptation), and then no force for additional 1 min (post-adaptation), and (b) overground walking. In the "varied" condition, the magnitude of force was randomly changed across steps between 30% and 100% of the predetermined amount. In the abrupt condition, the magnitude of force was kept constant at 100% of the predetermined amount. Participants exhibited greater improvements in weight shift toward the paretic side (p

Posttraumatic osteoarthritis (PTOA) is a subset of osteoarthritis (OA) resulting from the integrated outcome of joint injury, accounting for more than 12% of the overall OA cases. Although current therapies restore joint kinematics and alleviate inflammation, more than 20% patients undergo the unexpected progression of PTOA. Exercise is widely recommended to patients with OA and treadmill training is effective in preventing osteoarthritic changes in PTOA animals. However, the understanding gap of modified treadmill exercise models with different exercise dose and loading weight still exists. To evaluate the effects of body weight-supported treadmill training on PTOA, 30 rats were divided into the sham group (n = 6) and the PTOA group (n = 24) which were further assigned into three subgroups including the sedentary, the treadmill walking (TW), and the body weight-supported treadmill training (BWSTT) groups. The training groups were subjected to 4-week treadmill training at the speed of 15 m/min for 30 min/d, 5 d/wk. Then the tibias were elevated by histological staining, immunohistochemical staining, and micro-computed tomography. In our results, the significant OA-relevant changes in cartilage-subchondral bone unit were observed in the PTOA groups after surgery, characterized by cartilage degradation and subchondral bone remodeling. After 4-week treadmill training, the OA-relevant changes in cartilage-subchondral bone unit were alleviated and BWSTT is more efficient to maintain cartilage integrity and attenuate the subchondral bone loss and remodeling than TW. In conclusion, BWSTT is a promising and favorable treatment of PTOA slowing down the development of PTOA by reprogramming the cartilage-subchondral unit.

Although the goat is an established animal model in anterior cruciate ligament (ACL) research, in vivo kinematics associated with ACL deficiency have not been previously described in this species. Three-dimensional knee kinematics were determined before and after unilateral ACL transection in eight goats. Fluoroscopic imaging of the knees during treadmill walking and force-platform gait analysis during over-ground walking were performed prior to ACL transection, and 2 weeks, 3 months, and 6 months after ACL transection. Transient lameness of the ACL-transected limb was noted in all goats but resolved by 3 months post-ACL transection. Increased extension of 8.7° to 17.0° was noted throughout the gait cycle in both the ACL-transected and the contralateral unaffected knees by 3 months post-ACL transection, in a bilaterally symmetric pattern. Peak anterior tibial translation increased by 3 to 6 mm after ACL transection and persisted over the 6-month study period. No changes in axial rotation or abduction angle were observed after ACL transection. Unilateral ACL deficiency in goats resulted in persistent kinematic alterations, despite the resolution of lameness by 3 months post-ACL transection.

Coupling behavioral measures and brain imaging in naturalistic, ecological conditions is key to comprehend the neural bases of spatial navigation. This highly integrative function encompasses sensorimotor, cognitive, and executive processes that jointly mediate active exploration and spatial learning. However, most neuroimaging approaches in humans are based on static, motion-constrained paradigms and they do not account for all these processes, in particular multisensory integration. Following the Mobile Brain/Body Imaging approach, we aimed to explore the cortical correlates of landmark-based navigation in actively behaving young adults, solving a Y-maze task in immersive virtual reality. EEG analysis identified a set of brain areas matching state-of-the-art brain imaging literature of landmark-based navigation. Spatial behavior in mobile conditions additionally involved sensorimotor areas related to motor execution and proprioception usually overlooked in static fMRI paradigms. Expectedly, we located a cortical source in or near the posterior cingulate, in line with the engagement of the retrosplenial complex in spatial reorientation. Consistent with its role in visuo-spatial processing and coding, we observed an alpha-power desynchronization while participants gathered visual information. We also hypothesized behavior-dependent modulations of the cortical signal during navigation. Despite finding few differences between the encoding and retrieval phases of the task, we identified transient time-frequency patterns attributed, for instance, to attentional demand, as reflected in the alpha/gamma range, or memory workload in the delta/theta range. We confirmed that combining mobile high-density EEG and biometric measures can help unravel the brain structures and the neural modulations subtending ecological landmark-based navigation.

To examine the validity of popular smartphone accelerometer applications and a consumer activity wristband compared to a widely used research accelerometer while assessing the impact of the phone's position on the accuracy of step detection. Twenty volunteers from 2 different age groups (Group A: 18-25 years, n = 10; Group B 45-70 years, n = 10) were equipped with 3 iPhone SE smartphones (placed in pants pocket, shoulder bag, and backpack), 1 Samsung Galaxy S6 Edge (pants pocket), 1 Garmin Vivofit 2 wristband, and 2 ActiGraph wGTX+ devices (worn at wrist and hip) while walking on a treadmill (1.6, 3.2, 4.8, and 6.0 km/h) and completing a walking course. All smartphones included 6 accelerometer applications. Video observation was used as gold standard. Validity was evaluated by comparing each device with the gold standard using mean absolute percentage errors (MAPE). The MAPE of the iPhone SE (all positions) and the Garmin Vivofit was small (

Objective: To determine the intra-rater reliability and precision of measurement of lumbar multifidus (LM) and transversus abdominis (TrA) thickness using freehand ultrasound imaging (USI) in a range of static and dynamic conditions. Methods: Fifteen asymptomatic participants performed a range of exercises whilst USI was used to measure absolute muscle thickness and change in muscle thickness from rest. Exercise conditions included the abdominal drawing in manoeuvre (ADIM), active straight leg raise (ASLR), contralateral arm lift, both unloaded (CAL) and loaded (LCAL), treadmill walking (WALK) and using the Functional Re-adaptive Exercise Device (FRED). Intra- and inter-day reliability was assessed using intraclass correlation coefficients (ICC), and standard error of measurement was used to assess measurement precision. Results: Good to excellent reliability was achieved for TrA and LM absolute thickness in all conditions. Measurement precision for absolute LM thickness was ≤2.8mm for CAL, ≤1.8mm for LCAL, ≤3.1mm for WALK and ≤3.8mm for FRED, and for absolute TrA thickness was ≤0.6mm for ADIM, ≤0.5mm for ASLR, ≤0.7mm for WALK and ≤0.5mm for FRED. Good to excellent reliability was achieved for TrA and LM relative muscle thickness in all conditions. Measurement precision for relative LM thickness was ≤3.7% for CAL, ≤3.8% for LCAL, ≤6.3% for WALK and ≤7.6% for FRED, and for relative TrA thickness was ≤13.6% for ADIM, ≤6.9% for ASLR, ≤11.1% for WALK and ≤7.2% for FRED. Conclusions: Acceptable reliability and precision of measurement is achieved for absolute and relative measures of deep spinal muscle thickness using freehand USI in relatively static and dynamic exercises.

The purpose of this study was to compare knee extension torque variability in patients with ACL reconstructed knees before and after exercise. Thirty two patients with an ACL reconstructed knee (ACL-R group) and 32 healthy controls (control group) completed measures of maximal isometric knee extension torque (90° flexion) at baseline and following a 30-min exercise protocol (post-exercise). Exercise included 30-min of repeated cycles of inclined treadmill walking and hopping tasks. Dependent variables were the coefficient of variation (CV) and raw-change in CV (ΔCV): CV = (torque standard deviation/torque mean x 100), ΔCV = (post-exercise – baseline). There was a group-by-time interaction (p = 0.03) on CV. The ACL-R group demonstrated greater CV than the control group at baseline (ACL-R = 1.07 ± 0.55, control = 0.79 ± 0.42, p = 0.03) and post-exercise (ACL-R = 1.60 ± 0.91, control = 0.94 ± 0.41, p = 0.001). ΔCV was greater (p = 0.03) in the ACL-R group (0.52 ± 0.82) than control group (0.15 ± 0.46). CV significantly increased from baseline to post-exercise (p = 0.001) in the ACL-R group, while the control group did not (p = 0.06). The ACL-R group demonstrated greater knee extension torque variability than the control group. Exercise increased torque variability more in the ACL-R group than control group. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1165–1170, 2015.

Sheep are a predominant animal model used to study a variety of orthopedic conditions. Understanding and controlling the in-vivo loading environment in the sheep hind limb is often necessary for investigations relating to bone and joint mechanics. The purpose of this study was to develop a musculoskeletal model of an adult sheep hind limb and investigate the effects of treadmill walking speed on muscle and joint contact forces. We constructed the skeletal geometry of the model from computed topography images. Dual-energy x-ray absorptiometry was utilized to establish the inertial properties of each model segment. Detailed dissection and tendon excursion experiments established the requisite muscle lines of actions. We used OpenSim and experimentally-collected marker trajectories and ground reaction forces to quantify muscle and joint contact forces during treadmill walking at 0.25 m• s−1 and 0.75 m• s−1. Peak compressive and anterior–posterior tibiofemoral contact forces were 20% (0.38 BW, p = 0.008) and 37% (0.17 BW, p = 0.040) larger, respectively, at the moderate gait speed relative to the slower speed. Medial–lateral tibiofemoral contact forces were not significantly different. Adjusting treadmill speed appears to be a viable method to modulate compressive and anterior–posterior tibiofemoral contact forces in the sheep hind limb. The musculoskeletal model is freely-available at www.SimTK.org. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1128–1133, 2015.

Introduction: To assess the effect of aging on stretch reflex modulation during walking, soleus H-reflexes obtained in 15 middle-aged (mean age 56.4 ± 6.9 years) and 15 young (mean age 23.7 ± 3.9 years) subjects were compared. Methods: The H-reflex amplitude, muscle activity (EMG) of the soleus and tibialis anterior muscles, and EMG/H-reflex gain were measured during 4-km/h treadmill walking. Results: The normalized H-reflex amplitude was lower in the swing phase for the middle-aged group, and there was no difference in muscle activity. EMG/H-reflex gain did not differ between groups. Conclusions: H-reflex amplitude during walking was affected by aging, and changes during the swing phase could be seen in the middle-aged subjects. Subdividing the 2 age groups into groups of facilitated or suppressed swing-phase H-reflex revealed that the H-reflex amplitude modulation pattern in the group with facilitated swing-phase H-reflex may be influenced by aging. Muscle Nerve 51: 419–425, 2015

Post-exercise heart rate recovery (HRR) has been proposed as a measure of cardiac autonomic dysfunction in apparently healthy adults. We aimed to determine the effects of a lifestyle intervention on HRR among clinically obese premenopausal women. A randomized controlled trial was conducted to investigate the effects of a 3-month non-dieting lifestyle intervention program on cardiorespiratory fitness (CRF) and HRR among healthy clinically obese premenopausal women. Thirty-one were randomly assigned to 3-month intensive lifestyle intervention and 31 served as controls. Sixty-one participants performed a maximal treadmill walking test with metabolic gas exchange. Baseline anthropometric measures were closely related to HRR at 1min, which may indicate reduced parasympathetic reactivation. Post-exercise HRR at 60s (HRR60) increased from 21.3±6.2 to 27.8±10.2bpm in the intervention group compared with a smaller reduction (26.8±12.3 to 24.5±9.9bpm) in controls (test for interaction P=0.0001). HRR120 showed a significant effect of time (P=0.0002) with no significant interaction with lifestyle intervention. A significant increase in VO2peak was evident in the lifestyle group (21.6 to 23.6mL/kg/min) compared with a modest reduction in the controls (22.6 to 21.6mL/kg/min; test for interaction, P=0.001). Clinically obese healthy premenopausal women achieved significant improvements in HRR60 and VO2peak following a 3-month intensive lifestyle intervention. © 2012 John Wiley & Sons A/S.

Indirect evidence that the motor cortex and the corticospinal tract contribute to the control of walking in human subjects has been provided in previous studies. In the present study we used coherence analysis of the coupling between EEG and EMG from active leg muscles during human walking to address if activity arising in the motor cortex contributes to the muscle activity during gait. Nine healthy human subjects walked on a treadmill at a speed of 3.5–4 km h−1. Seven of the subjects in addition walked at a speed of 1 km h−1. Significant coupling between EEG recordings over the leg motor area and EMG from the anterior tibial muscle was found in the frequency band 24–40 Hz prior to heel strike during the swing phase of walking. This signifies that rhythmic cortical activity in the 24–40 Hz frequency band is transmitted via the corticospinal tract to the active muscles during walking. These findings demonstrate that the motor cortex and corticospinal tract contribute directly to the muscle activity observed in steady-state treadmill walking.

Freezing of gait (FOG) is a clinically defined phenomenon of Parkinson's disease (PD). Recent evidence suggests that subtle FOG episodes can be elicited in a gait laboratory using suddenly appearing obstacles during treadmill walking. We evaluated which quantitative gait parameters identify such subtle FOG episodes. We included 10 PD patients with FOG, 10 PD patients without FOG, and 10 controls. Subjects walked on a motorized treadmill while avoiding unexpectedly appearing obstacles. Treadmill walking was videotaped, and FOG episodes were identified by two independent experts. Gait was also analyzed using detailed kinematics. Knee joint signals were processed using time-frequency analysis with combinations of sliding fast Fourier transform and wavelets transform. Twenty FOG episodes occurred during treadmill walking in 5 patients (all with clinically certified FOG), predominantly in relation to obstacle avoidance. FOG was brief when it occurred just before or after obstacle crossing and was characterized by short, rapid steps. Frequency analysis showed a typical qualitative pattern: before the FOG episode an increase in dominant frequency in the 0 to 3 Hz band (festination), followed by decreased power in 0 to 3 Hz band and an increased power in the 3 to 8 Hz band during the FOG episode. This pattern led to an increased FOG index as a qualitative measure. These approaches detected even very brief FOG with acceptable sensitivity (75-83%) and specificity (>95%). We conclude that time-frequency analysis is an appropriate approach to detect brief and subtle FOG episodes. Future work will need to decide whether this approach can support or even replace expert clinical opinion.

Aim The aim of this study was to compare the oxygen cost (V(O2)) of walking and running, as well as aerobic fitness, in children with and without developmental coordination disorder (DCD). Method Thirty-one males (17 with DCD and 14 in a comparison group; mean age 8 y 7 mo, SD 1 y 3 mo and 8 y 5 mo, SD 1 y 2 mo respectively) were tested on two separate occasions at least 1 week apart. On the first visit, motor proficiency was assessed by the McCarron Assessment of Neuromuscular Development instrument, which was followed by the determination of maximal aerobic capacity (V(O2max)). The second visit involved 4-minute bouts of treadmill walking (at 4.3 km/h and 5.8 km/h) and running (at 7.8 km/h and 8.4 km/h). Oxygen consumption, heart rate, respiratory exchange ratio, rating of perceived exertion (RPE), step rate, and qualitative assessment of locomotion were obtained for each speed. Results Despite poorer locomotion proficiency, there was no significant difference in the oxygen cost of walking or running between males with and without DCD. However, the DCD group had significantly higher RPE while running at 7.8 km/h (p=0.011) and had greater difficulty achieving V(O2max), resulting in significantly lower scores for aerobic fitness. Interpretation The differences in locomotion proficiency between children with and without DCD are not large enough to affect the oxygen cost of locomotion. However, children with DCD are more likely to withdraw from exercising at higher intensities before achieving peak performance.

Freezing of gait (FOG) is a common and disabling feature of Parkinson's disease (PD). Detailed pathophysiological studies are hampered by the fact that FOG episodes are difficult to elicit in a gait laboratory. We evaluated whether the need to avoid sudden obstacles on a treadmill can provoke FOG. We included 21 PD patients (15 with self-reported off-period FOG). Patients were tested in the off-state. FOG during overground walking was assessed using a standardized gait trajectory and axial 360 degrees turns. Subsequently, patients walked on a motorized treadmill with suddenly appearing obstacles that necessitated compensatory stepping. Performance was videotaped, and presence of FOG was scored visually by two independent raters. Thirteen patients showed FOG during overground walking. During treadmill walking, obstacle avoidance was associated with 13 unequivocal FOG episodes in eight patients, whereas only one patient froze during undisturbed treadmill walking (Wilcoxon z = -2.0, P = 0.046). FOG episodes elicited by obstacle avoidance were brief (typically

The aim of this study was to determine the effects of a short-term high-intensity exercise program on diastolic function and glucose tolerance in obese individuals with and without metabolic syndrome (MetSyn). Obese men and women (BMI30 kg/m(2); 39-60 years) with and without the MetSyn (MetSyn 13; non-MetSyn 18) underwent exercise training consisting of 10 consecutive days of treadmill walking for 1 h/day at 70-75% of peak aerobic capacity. Subjects performed pre- and post-training testing for aerobic capacity, glucose tolerance (2-h meal test), and standard echocardiography. Aerobic capacity improved for both groups (non-MetSyn 24.0 +/- 1.6 ml/kg/min vs. 25.1 +/- 1.5 ml/kg/min; MetSyn 25.2 +/- 1.8 ml/kg/min vs. 26.2 +/- 1.7 ml/kg/min, P0.05). Glucose area under the curve (AUC) improved in the MetSyn group (1,017 +/- 58 pmol/l/min vs. 883 +/- 75 pmol/l/min, P0.05) with no change for the non-MetSyn group (685 +/- 54 pmol/l/min vs. 695 +/- 70 pmol/l/min). Isovolumic relaxation time (IVRT) improved in the MetSyn group (97 +/- 6 ms vs. 80 +/- 5 ms, P0.05), and remained normal in the non-MetSyn group (82 +/- 6 ms vs. 86 +/- 5 ms). No changes in other diastolic parameters were observed. The overall reduction in IVRT was correlated with a decrease in diastolic blood pressure (DBP) (r = 0.45, P0.05), but not with changes in glucose tolerance. Body weight did not change with training in either group. A 10-day high-intensity exercise program improved diastolic function and glucose tolerance in the group with MetSyn. The reduction in IVRT in MetSyn was associated with a fall in blood pressure. These data suggest that it may be possible to reverse early parameters of diastolic dysfunction in MetSyn with a high-intensity exercise program.

The purpose of this study was to examine the concurrent validity of the Personal Activity Monitor (PAM) accelerometer relative to the Actigraph accelerometer using oxygen consumption as a reference, and to assess the test-retest reliability of the PAM. Thirty-two fit, normal weight adults (aged 21-54) performed two activities, treadmill walking and stair walking, while wearing the PAM, the Actigraph and the Cosmed K4b2. Correlation coefficients and agreement in absolute energy expenditure (EE) levels between PAM, Actigraph and Cosmed were calculated. The test-retest reliability was examined among 296 PAM's using a laboratory shaker. Intraclass correlation coefficients (ICC) and coefficient of variation (CV) were determined. Correlations for treadmill walking and stair walking, respectively, were r 2=0.95 and r2=0.65 for PAM with Actigraph, r 2=0.82 and r2=0.93 for PAM with VO2 and r 2=0.64 and 0.74 for Actigraph with VO2. Both the PAM and Actigraph underestimated EE during treadmill and stair walking by a substantial amount. The test-retest reliability of the PAM was high [ICC=0.80; 95% confidence interval (CI) (0.28;0.92) and intra-CV=1.5%]. The PAM and Actigraph accelerometer are comparable in assessing bodily movement during treadmill and stair walking. The PAM is a valid device to rank subjects in EE and can be useful in collecting objective data to monitor habitual physical activity. Copyright © 2009 The Authors.

To examine the reliability and validity of the SenseWear Pro 2 Armband (SWA; Body Media, Pittsburgh, PA) during rest and exercise compared with indirect calorimetry (IC) in obese individuals.Energy expenditure was assessed during rest with the SWA and IC in 142 obese adults (37 men and 105 women, BMI = 42.3 +/- 7.0) and in 25 lean and overweight adults (BMI = 25.3 +/- 3.2) who were used as a comparison group. Twenty-nine of the obese adults also participated in three separate short exercise sessions including cycle ergometry, stair stepping, and treadmill walking.The repeatability of SWA estimates in obese subjects was high (r = 0.88, p0.001). The SWA generally underestimated the resting energy expenditure (REE) (1811 +/- 346 vs. 1880 +/- 382 kcal/d) and highly overestimated the energy expenditure during the exercise sessions in obese individuals. REE estimations by SWA were significantly correlated with fat-free mass (r = 0.88, p0.001). Bland-Altman plots based statistical analysis for the estimated REE, and measured IC showed a low agreement (Total Error20% but Systematic Error5%) between the two methods in obese subjects, although they showed a high correlation and a very good agreement in lean and overweight patients.The SWA is an easy to handle, practical, new portable device for measuring energy expenditure. The accuracy of the SWA appeared to be poor in the obese subjects we examined, especially those with high REE both in rest and exercise. We believe that it is necessary to incorporate new, obesity-specific algorithms in the relative software.

High-altitude Tibetans undergo a pattern of adaptations to chronic hypoxia characterized, among others, by a more efficient aerobic performance compared with acclimatized lowlanders. To test whether such changes may persist upon descent to moderate altitude, oxygen uptake of 17 male Tibetan natives lifelong residents at 3500–4500 m was assessed within 1 month upon migration to 1300 m. Exercise protocols were: 5 min treadmill walking at 6 km h−1 on increasing inclines from +5 to +15% and 5 min running at 10 km h−1 on a +5% grade. The data (mean ±s.e.m.) were compared with those obtained on Nepali lowlanders. When walking on +10, +12.5 and +15% inclines, net of Tibetans was 25.2 ± 0.7, 29.1 ± 1.1 and 31.3 ± 0.9 ml kg−1 min−1, respectively, i.e. 8, 10 and 13% less (P < 0.05) than that of Nepali. At the end of the heaviest load, blood lactate concentration was lower in Tibetans than in Nepali (6.0 ± 0.9 versus 8.9 ± 0.6 mm; P < 0.05). During running, of Tibetans was 35.1 ± 0.8 versus 39.3 ± 0.7 ml kg−1 min−1 (i.e. 11% less; P < 0.01). In conclusion, during submaximal walking and running at 1300 m, Tibetans are still characterized by lower aerobic energy expenditure than control subjects that is not accounted for by differences in mechanical power output and/or compensated for by anaerobic glycolysis. These findings indicate that chronic hypoxia induces metabolic adaptations whose underlying mechanisms still need to be elucidated, that persist for at least 1 month upon descent to moderate altitude.

Introduction: Walking programmes are recommended as part of the initial treatment for intermittent claudication (IC). However, for many patients factors such as frailty, the severe leg discomfort associated with walking and safety concerns about exercising in public areas reduce compliance to such prescription. Thus, there is a need to identify a mode of exercise that provides the same benefits as regular walking while also offering convenience and comfort for these patients. The present study aims to provide evidence for the first time of the efficacy of a supervised cycle training programme compared with a conventional walking programme for the treatment of IC. Methods: Thus far 33 patients have been randomized to: a treadmill-training group (n = 12); a cycle-training group (n = 11); or a control group (n = 10). Training groups participated in three sessions of supervised training per week for a period of 6 weeks. Control patients received no experimental intervention. Maximal incremental treadmill testing was performed at baseline and after the 6 weeks of training. Measures included pain-free (PFWT) and maximal walking time (MWT), continuous heart rate and gas-analysis recording, and ankle-brachial index assessment. Results: In the treadmill trained group MWT increased significantly from 1016.7 523.7 to 1255.2 432.2 s (P < 0.05). MWT tended to increase with cycle training (848.72 333.18 to 939.54 350.35 s, P = 0.14), and remained unchanged in the control group (1555.1 683.23 to 1534.7 689.87 s). For PFWT, there was a non-significant increase in the treadmill-training group from 414.4 262.3 to 592.9 381.9 s, while both the cycle training and control groups displayed no significant change in this time (226.7 147.1 s to 192.3 56.8 and 499.4 503.7 s to 466.0 526.1 s, respectively). Conclusions: These preliminary results might suggest that, unlike treadmill walking, cycling has no clear effect on walking performance in patients with IC. Thus the current recommendations promoting walking based programmes appear appropriate. The present study was funded by the National Heart Foundation of Australia.

Objective: This study was designed to validate accelerometer-based activity monitors against energy expenditure (EE) in children; to compare monitor placement sites; to field-test the monitors; and to establish sedentary, light, moderate, and vigorous threshold counts. Research Methods and Procedures: Computer Science and Applications Actigraph (CSA) and Mini-Mitter Actiwatch (MM) monitors, on the hip or lower leg, were validated and calibrated against 6-hour EE measurements by room respiration calorimetry, activity by microwave detector, and heart rate by telemetry in 26 children, 6 to 16 years old. During the 6 hours, the children performed structured activities, including resting metabolic rate (RMR), Nintendo, arts and crafts, aerobic warm-up, Tae Bo, treadmill walking and running, and games. Activity energy expenditure (AEE) computed as EE − RMR was regressed against counts to derive threshold counts. Results: The mean correlations between EE or AEE and counts were slightly higher for MM-hip (r = 0.78 ± 0.06) and MM-leg (r = 0.80 ± 0.05) than CSA-hip (r = 0.66 ± 0.08) and CSA-leg (r = 0.73 ± 0.07). CSA and MM performed similarly on the hip (inter-instrument r = 0.88) and on the lower leg (inter-instrument r = 0.89). Threshold counts for the CSA-hip were

Gravitational unloading leads to adaptations of the human body, including the spine and its adjacent structures, making it more vulnerable to injury and pain. The Functional Re‐adaptive Exercise Device (FRED) has been developed to activate the deep spinal muscles, lumbar multifidus (LM) and transversus abdominis (TrA), that provide inter‐segmental control and spinal protection. The FRED provides an unstable base of support and combines weight bearing in up‐right posture with side alternating, elliptical leg movements, without any resistance to movement. The present study investigated the activation of LM, TrA, obliquus externus (OE), obliquus internus (OI), abdominis, and erector spinae (ES) during FRED exercise using intramuscular fine‐wire and surface EMG. Nine healthy male volunteers (27 ± 5 years) have been recruited for the study. FRED exercise was compared with treadmill walking. It was confirmed that LM and TrA were continually active during FRED exercise. Compared with walking, FRED exercise resulted in similar mean activation of LM and TrA, less activation of OE, OI, ES, and greater variability of lumbo‐pelvic muscle activation patterns between individual FRED/gait cycles. These data suggest that FRED continuously engages LM and TrA, and therefore, has the potential as a stationary exercise device to train these muscles.

The day-to-day variation in oxygen consumption (V˙O2) and energy expenditure (EE) during horizontal treadmill walking was measured using indirect calorimetry in 20 female adolescents (mean age 17·3 years). Two different walking speeds were used: 5 km h−1 and an individually convenient speed of 3·0 km h−1 (mean). The two sets of measurements were performed on 2 consecutive days, and great care was taken to minimize possible disturbing factors. The mean V˙O2 was 919 ml min−1 at 5 km h−1 and 622 ml min−1 at the individual speed, and the mean values of EE were 4·5 kcal min−1 and 3·1 kcal min−1 respectively. The individual day-to-day variation in V˙O2 (at 5 km h−1) was between −11·7% and +12·6% of the mean V˙O2. The coefficient of variation (CV) was 6·4% when values were calculated in ml min−1 kg−1. The energy expenditure varied somewhat less between the 2 days (CV = 5·7%). The corresponding value for EE when walking at the individual speed was 7·2%, and the mean day-to day variation in V˙O2 was 7·5% (CV). The rate of perceived exertion according to Borg's scale was lower on day 2 (11·9) compared with day 1 (13·0) when walking at 5 km h−1. There was no difference in heart rate between the 2 days. It is concluded that EE varies somewhat less than V˙O2 on successive days, probably because of an interchangeable relationship between breathing gases, depending on which substrate is used for combustion. When using V˙O2 and EE for evaluation of physical capacity, the day-to-day variation in the measurements must be taken into consideration.

OBJECTIVE: For the purpose of prescribing exercise intensity, the American College of Sports Medicine (ACSM) provides guidelines for relating the perceived level of exertion and the heart rate (HR) response during exercise, expressed either as a percentage of maximal HR or of HR reserve, to a percentage of maximal aerobic power (VO2max). However, because maximal HR and VO2max decline with age, it is possible that these guidelines are not appropriate for an older population. The purpose of this study was to evaluate in 60-to 72-year-old women the relationships among the common methods of prescribing exercise intensity. DESIGN: Participants were 112 healthy but sedentary women, aged 66 ± 4 years, who performed treadmill walking at four speeds. SETTING: Subjects were recruited from the community, and exercise tests were performed at a university laboratory facility. MEASUREMENTS: VO2max and maximal HR were determined during treadmill walking. The HR and VO2 responses to walking 6 minutes at each of four speeds ranging from 67 to 107 m/min, along with ratings of perceived exertion (RPE) and plasma lactate levels, were determined on a separate day. RESULTS: The exercise bouts required an average of 55 ± 10%, 64 ± 12%, 77 ± 12%, and 91 ± 9% of VO2max. Corresponding HR values were 64 ± 8%, 70 ± 9%, 81 ± 10%, and 92 ± 7% of maximal HR, and they were within the expected ranges based on ACSM guidelines. HR values as a percentage of HR reserve were much lower than expected based on the guidelines. RPE values were lower than expected at a given %VO2max, and plasma lactate levels were also relatively low, suggesting that older women are able to exercise at a higher percentage of VO2max than levels currently recommended. CONCLUSIONS: The results indicate that HR expressed as a percentage of maximal HR is an appropriate method of prescribing exercise intensity in healthy, sedentary 60- to 72-year-old women. The HR reserve method is not recommended in this population because it will likely result in the exercise being performed at a higher than expected percentage of VO2max.

Walking is a complex process and the physiotherapist must focus on physical signs as well as functional and practical tests to evaluate treatment. Measurement of energy expenditure during level walking is a useful objective parameter for assessing walking as being a valuable supplement to evaluate the outcome of physiotherapy. This study had two purposes. The first purpose was to investigate whether sampling and measurement of oxygen consumption were reproducible when using two different devices during walking on a treadmill. A second purpose was to find out whether the measurements were sensitive enough to reveal differences in energy expenditure and respiratory quotient (RO) during different walking speeds. Ten healthy students (mean age 22 years; range 20-25 years) volunteered in the test-retest of a slightly adjusted Deltatrac metabolic monitor. Thirteen volunteers (mean age 45 years; range 31-57 years) participated in the test-retest of Sensormedics 2900. In the first test, the subjects walked for 10 min in order to get a steady state both at an individual comfortable speed and at a preset speed. The retest was done with the same design and within 2 weeks. Nobody experienced any discomfort during the tests. The repeatability of measuring energy expenditure and RQ was acceptable for both methods and the methods were sensitive in revealing differences in energy expenditure during different walking speeds. The RQ were, however, too low when using the Deltatrac monitor, probably as a result of low air flow. We therefore conclude that only the method using Sensormedics 2900 may be used for the evaluation of energy expenditure during walking on a treadmill.

Objectives The objective is to understand the walking energy expenditure of women in urban environments (i.e., over-ground), using mass, velocity, gradient (incline and decline), and burden as predictors. In addition, we use an equation to determine the gradient associated with the minimum energy expenditure of walking. Methods To do this, we assessed the volumetric consumption of oxygen (VO2) of ten females (ages: 22–40 years) with a portable Cosmed K4b2 device. Participants walked at three self-selected, over-ground velocities (slow, normal, and fast) on five gradients (0%, +/−7.5%, +/− 12.4%) in different urban community settings burdened (10 kg) and unburdened. We performed a multilinear regression controlling for repeated measures to determine the best predictive equation for VO2. The first derivative of our equation was used to find the gradient for minimal VO2. Results Our equation explains 79% of the variation in VO2 and indicates that over-ground walking is similar to treadmill walking, except that the gradient associated with the minimal energy expenditure of walking is steeper (−11% to −20%) than that established from treadmill walking. Conclusions Although our overall equation is an accurate predictor of VO2 for all velocities, burden, incline, and decline in this group, further research needs to be conducted to examine kinetic, kinematic, and velocity interactions in over-ground walking.

Unselected patients suffering from intermittent claudication (n = 148) were invited to take part in a prospective study. Physical examination and several circulatory investigations were performed including a treadmill walking test, bicycle ergometry and a quality of life examination (Sickness Impact Profile, SIP, technique). The SIP has been reported to be sensitive enough to identify specific dysfunction profiles in several clinical conditions, but it has not been used on patients with intermittent claudication. The aim of this study was to determine to what extent quality of life was influenced by reduced walking ability in patients with intermittent claudication. If so, the SIP technique should then be a useful tool for determination of the degree of reduced exercise capacity in patients who may benefit from surgery instead of conservative treatment. A majority of the SIP categories, Sleep and rest, Emotional behaviour, Body care and movement, Home management, Mobility, Social interaction, Ambulation and Overall SIP were shown to be useful in confirming objective dysfunctions in our patients. The correlation between maximum walking ability and SIP scores indicated an approximate cut-off limit at 70 W walking capacity. Thus, significant reductions in everyday life function were demonstrated in patients with maximum walking ability below 70 W. Patients with intermittent claudication also suffered from several other dysfunctions in addition to walking disability. These factors may, as well, impact on quality of life without walking disability. Our results demonstrated that quality of life assessment by the SIP technique was a sensitive method for evaluation of overall dysfunction in patients with intermittent claudication.(ABSTRACT TRUNCATED AT 250 WORDS)

The purpose of this study was to investigate the use of the heartrate (HR) version of the energy expenditure index (EEIHR) as a proxy for measurement of walking oxygen consumption (VO2) in children with cerebral palsy (CP). Thirteen children (eight males, five females; mean age 11 years 2 months [SD 3 years], age range 6 to 15 years) with hemiplegic CP, participated in this study. The study was conducted over three sessions. During session 1, participants were familiarized with testing procedures and given 5 minutes of treadmill walking practice. In session 2, participants completed three 5-minute walking bouts on the treadmill at 0.67m x s(-1) to familiarize themselves with treadmill locomotion. During the final session participants walked at 0.67, 0.89, and 1.12m x s(-1) for 5 minutes while gross oxygen consumption (gross VO2; walking VO2/speed), net VO2 ([walking VO2-resting VO2]/speed), and EEIHR ([walking HR-resting HR]/speed) were measured during the last 2 minutes of each bout. Correlational analyses indicated no relationship (p>0.05) between measures of gross VO2 and EEIHR at each speed. Although no association was evident between net VO2 and EEIHR at 0.67 and 0.89m x s(-1), a moderate relationship (r=0.64; p

1. The breathing pattern, that is the changes in tidal volume (VT), and in inspiratory (TI) and expiratory (TE) durations, has been studied as ventilation increases in exercise. 2. Five healthy subjects were studied in steady-state exercise on a bicycle ergometer, breathing air, at two speeds of pedalling and at six different loads. The pattern was recorded for single breaths. Two of the subjects were also studied while walking on a treadmill with four combinations of speed and gradient. 3. In bicycle exercise, as the CO2 output increased mean VT increased, and mean TI and TE decreased, the absolute decrease in TI being small. The pedalling speed did not affect these relationships. 4. Individual breath durations showed no tendency to group around multiples of the period of rotation of the pedals. 5. In treadmill exercise, no clear influence of stride rate on respiratory rate could be found. The pattern was similar to that found in bicycle exercise. Again no grouping could be found. 6. No evidence of an effect of frequency of limb movement on breathing pattern in submaximal exercise has been found. The selection of breathing pattern seems to be unrelated to the nature of the stimulus but closely geared to the metabolic needs of the body.

Measurements of body temperature, respiratory gas exchange, sweat evaporation rate and circulating levels of catecholamines, lactate, pyruvate, free fatty acids and glucose were made in seven patients susceptible to malignant hyperpyrexia (MHS) and in seven control subjects during 2 h of treadmill walking at 40% of maximum oxygen consumption. These studies took place in an ambient temperature of 22 degrees C. The MHS patients displayed the same thermoregulatory, plasma catecholamine and metabolic responses as the control subjects. The results of the present study suggest that non-competitive, low-intensity, steady-state exercise need not be contraindicated for MHS patients.