Walking Economy Research Articles

Tissue oxygenation in peripheral muscles and functional capacity in cystic fibrosis: a cross-sectional study.

What is the central question of this study? How do peripheral muscle tissue oxygenation and physical conditioning levels of children and adolescents with cystic fibrosis compare to demographically matched controls? What is the main finding and its importance? Children and adolescents with cystic fibrosis consumed more oxygen, more quickly and exhibited slower recovery, demonstrating that there may have been deficiencies in oxygen supply related to both oxygen uptake and oxygen transport. Cystic fibrosis affects skeletal muscle performance and functional capacity. However, it is currently unclear how peripheral muscle behaviour is affected, especially in children and adolescents. To examine this, we compared tissue oxygenation of children and adolescents with cystic fibrosis against healthy volunteers. We also evaluated the functional capacity of participants via the modified shuttle test (MST) and assessed for associations between performance and near-infrared spectroscopy. A total of 124 participants enrolled. Participants were divided into either the cystic fibrosis group (CFG) or the healthy group (HG). Statistical comparisons between groups were evaluated with the Mann-Whitney U test and associations with functional capacity were evaluated using Spearman's correlation coefficient. CFG volunteers scored lower on the MST compared to the HG. They walked shorter distances (P=0.001) with less efficiency because they performed the tests with a less efficient walking economy (P=0.001) and a greater deoxyhaemoglobin concentration (P=0.001). Further, they experienced reduced tissue oxygen saturation (P=0.037) faster than the HG. As a result, they presented lower respiratory (P=0.001) and lower heart (P=0.001) rate values at the end of the MST, with a longer post-test heart rate recovery time (P=0.005). There was a significant association between deoxygenation time and functional capacity. The CFG consumed more oxygen, more quickly, with a slower recovery, reflecting impairments in the dynamics of muscle oxygen extraction. The results suggest differences in functional capacity and haemodynamic recovery in children and adolescents with cystic fibrosis.

Oxygen cost of over-ground walking in persons with mild-to-moderate Parkinson’s disease

BackgroundOxygen (O2) cost of walking is a physiological marker of walking dysfunction and reflects the amount of O2 consumed per kilogram of body weight per unit distance walked. The onset of walking dysfunction (i.e., reduced walking speed and shorter stride length) is commonly observed in Parkinson’s disease (PD), even in the early stages of the disease. However, the O2 cost of walking has not been assessed in persons with PD. Research questionDoes O2 cost of walking differ between persons with PD and controls matched by age and sex? MethodsThe sample included 31 persons with mild-to-moderate PD (Hoehn and Yahr stages 2–3) and 31 age- and sex-matched controls in this cross-sectional study. O2 consumption (VO2) was measured using a portable indirect calorimetry system during a 6-min period of over-ground walking at a normal comfortable speed, and the O2 cost of walking was calculated based on the ratio of net relative VO2 (ml kg−1 min−1) and speed (m min−1). ResultsThere were no differences in resting VO2, steady-state VO2, and over-ground walking speed between persons with PD and controls (p > 0.05). There was a significant difference in the O2 cost of walking between persons with PD and healthy controls (p < 0.01) such that persons with PD had a higher O2 cost of walking. The mean(SD) O2 cost of walking for persons with PD was 0.179 (0.038) ml kg−1 m−1, and the O2 cost of walking for healthy controls was 0.153 (0.024) ml kg−1 m−1. SignificancePersons with PD demonstrated a higher O2 cost of walking compared with controls, and this may reflect worse walking economy in PD. The possibility of worse walking economy under free-living conditions may result in reduced community ambulation and participation.

Bicycling Exercise Helps Maintain a Youthful Metabolic Cost of Walking in Older Adults.

The decline of walking performance is a key determinant of morbidity among older adults. Healthy older adults have been shown to have a 15-20% lower walking economy compared with young adults. However, older adults who run for exercise have a higher walking economy compared with older adults who walk for exercise. Yet, it remains unclear if other aerobic exercises yield similar improvements on walking economy. The purpose of this study was to determine if regular bicycling exercise affects walking economy in older adults. We measured metabolic rate while 33 older adult "bicyclists" or "walkers" and 16 young adults walked on a level treadmill at four speeds between (0.75-1.75m/s). Across the range of speeds, older bicyclists had a 9-17% greater walking economy compared with older walkers (p = .009). In conclusion, bicycling exercise mitigates the age-related deterioration of walking economy, whereas walking for exercise has a minimal effect on improving walking economy.

A Backpack Minimizing the Vertical Acceleration of the Load Improves the Economy of Human Walking.

Loaded walking with a rucksack results in both gravitational and inertial forces of the load that must be borne by human carriers. The inertial force may be the source of metabolic burden and musculoskeletal injuries. This paper presents a lightweight backpack with a disturbance observer-based acceleration control to minimize the inertial force. The backpack was evaluated by seven participants walking on a treadmill at 5 km h-1 with a 19.4 kg load. Three experimental conditions were involved, including walking with a locked load (LOCKED), with an acceleration-controlled load (ACTIVE) using the designed backpack and walking with the same load using a rucksack (RUCKSACK). Our results showed that the ACTIVE condition reduces the load acceleration by 98.5% on average, and reduce the gross metabolic power by 8.0% and 11.0% as compared to LOCKED and RUCKSACK conditions respectively. The results demonstrate that the proposed active backpack can improve the loaded walking economy compared with a conventional rucksack in level-ground walking.

Overground Locomotor Training In Parkinson's Disease: Effects On Walking Economy And Performance Fatigability

Walking economy (WE) is a measure of metabolic energy expenditure relative to walking speed, and, when elevated, may contribute to decreased capacity and performance relative to sustained walking in people with Parkinson’s Disease (PD). Coupled with performance fatigability (PF), these factors may increase disability in this population. Although sustained walking underlies many daily activities and impacts physical activity for many people with PD, responses to walking-specific interventions to develop optimal training methods have not been fully investigated in this population. PURPOSE: Determine changes in WE, PF, and physiologic response during sustained walking following a task-specific, performance-based overground locomotor training program (OLT) in people with mild/moderate PD. METHODS: 7 males and 2 females (68.9 ± 7.1 years old, H&Y scores 1-3) completed a 12-week program of 24 OLT sessions lasting 45 - 60 minutes each. Subjects were coached through multiplanar movement drills based on components of the gait cycle emphasizing power, stability and stepping under aerobically challenging conditions (ClinicalTrials.gov. - NCT03864393). Walking performance was measured during an overground 10-minute walk test (10MWT) by total distance (TD) and PF (Δ speed/total distance). During the final 5 minutes of the 10MWT, average heart rate (HR), oxygen consumption (V̇O2), and carbon dioxide production (V̇CO2) were recorded using a portable metabolic system. These values were divided by the average speed in the final 5 minutes of the 10MWT to assess WE and physiologic response. RESULTS: There were moderate to large, significant effects for TD (925.77 ± 175.67 vs 1018.37 ± 133.83, p=0.019, d=0.59), PFS (1.11 ± 0.19 vs 0.98 ± 0.13, p=0.013, d=0.79) and HR/speed (76.46 ± 7.69 vs 71.49 ± 6.71 bpm/m/s, p=0.05, d=0.69). There were small, non-significant effects for V̇O2/speed (12.14 ± 1.99 vs 11.47 ± 2.89 mL/min/kg/m/s, d=0.34) and V̇CO2/speed (790.56 ± 196.8 vs 778.93 ± 197.94 mL/min/m/s, d=0.06). CONCLUSIONS: OLT improved WE and PFS during sustained walking. Despite a moderate effect, HR changes in response to OLT are difficult to interpret without additional measures of cardiorespiratory function. Larger and more mechanistic studies can provide further insight into this potential adaptation.

Effects of Lightweight Wearable Ankle Exoskeleton in an Individual With Parkinson Disease

Background: This is a feasibility study aimed to investigate the effects of a novel lightweight ankle exoskeleton on gait and balance in an individual with Parkinson disease (PD). Case Description: An 85-year old woman with a 5-year history of PD (Hoehn and Yahr stage 2.5) participated in the study. The participant received 4 visits over 4 weeks including 1 evaluation and three 30-minute training sessions wearing the ankle exoskeleton. Results: The participant demonstrated a 26% reduction in metabolic cost during walking and nearly 10% improvement in peak anterior-posterior center-of-pressure displacement during balance testing with untethered exoskeleton assistance compared with baseline. Conclusion: Participant-specific ankle exoskeleton is a feasible and safe intervention that can improve walking economy as well as balance in individuals with PD.

Minimalist style boot improves running but not walking economy in trained men

This study examined movement economy under load with 1000 g minimalist (MIN) vs. 1600 g traditional (TRD) style boots. Fourteen trained, male participants completed a VO2peak test (46.6 ± 7.3 ml/kg/min) while wearing a 16 kg external load. Treadmill speeds for the running economy (RE) trials were determined by the slowest pace in which participants completed a full stage with a running gait pattern during the VO2peak test. Walking economy (WE) pace was 1.6 km/h slower than RE pace. During the second session, participants completed 5-min exercise bouts at WE and RE pace under load wearing MIN and TRD. There were no differences for any measured variables during WE trials. In contrast, RE (MIN = 2.95 ± 0.28 vs. TRD = 3.04 ± 0.30 L/min; p = .003: Cohen’s d = 0.32), respiratory exchange ratio (p < .001), and perceptual measures (p < .05) were all improved while wearing MIN. Practitioner summary: In trained men, 1000 g/pair minimalist style boots (MIN) resulted in improvements of approximately 3% and 5% for running economy and respiratory exchange ratio versus 1600 g/pair traditional boots while wearing a 16 kg kit. Perceptual responses, including comfort, also favoured MIN. These effects were not found at walking pace. Abbreviations: MIN: minimalist style boots; TRD: traditional style boots; RE: running economy; WE: walking economy; ES: effect size; RER: respiratory exchange ratio; HR: heart rate

When mechanical work meets energetics: Obese versus non-obese children walking.

What is the central question of this study? The aim was to compare the cost of transport and mechanical work between obese and non-obese children at different walking speeds. What is the main finding and its importance? Our data show that the cost of transport, mechanical efficiency and work are similar and directly mass dependent in obese and non-obese children. The optimal walking speed (most economical walking speed) is reduced in obese children. Although studies have shown the influence of gait biomechanics on the metabolic economy in obese adults and adolescents, little is known regarding obese children. We compared the metabolic cost of transport, apparent mechanical efficiency and gait biomechanics (assessed by mechanical energy fluctuations) in obese children (n=12; mean±SD: 8.6±0.51 years of age, 1.38±0.04m, 44.6±6.65kg, 24.1±3.50kgm-2 ) and age- and sex-matched non-obese children (n=12, 7.8±0.90 years of age, 1.31±0.08m, 26.8±2.24kg, 16.4±1.40kgm-2 ) while walking at different speeds (from 1 to 5kmh-1 ) on a treadmill. We found that the mechanical efficiency was higher at 3kmh-1 compared with the remaining speeds for both groups (P<0.05). Although the internal mechanical work has been greater in obese compared with non-obese children at 4 and 5kmh-1 , the external, total mechanical work and the mechanical efficiency remained similar between obese and non-obese children at all speeds. Likewise, the cost of transport was similar in the two groups, although the optimal walking speed was an average of 0.4kmh-1 slower in obese children. Clearly, these results show that the walking economy is associated with the total mechanical work in obese and non-obese children. Finally, the reduced functional mobility in obese children observed in previous studies seems to be associated with a reduction in optimal walking speed in comparison to non-obese children.

Chronic Eccentric Cycling Training Improves Walking Economy in Healthy Individuals

ABSTRACTBackground: Low muscular strength is associated with decline in ambulatory function. Progressive strength training has been demonstrated to improve physical functional outcomes. Because eccentric exercise is a potent stimulus for increasing muscle size, strength, and power, it has the potential to serve as a time-effective intervention to improve ambulatory function at a lower metabolic cost compared with traditional strength training. We examined the effect of a 6-week eccentric cycling training intervention on walking economy in healthy individuals.Methods: Eleven healthy individuals (age = 24 ± 3 years; body weight = 71 ± 9 kg; height = 1.7 ± 0.1 m) trained on an eccentric ergometer for 6 weeks (3×/week; 10–30 min; 54%–66% of maximum heart rate). The metabolic cost of walking was assessed 1 week prior to and 1 week following eccentric cycling training. Cost of walking was determined as the net energy cost (J·kg−1·s−1), divided by walking speed (m·s−1) during steady-state walking at 5 walking speeds (0.7, 1.11, 1.39, 1.67, and 1.9 m·s−1)Results: Posttraining cost of walking was significantly improved across all 5 walking speeds (0.7, 1.11, 1.39, 1.67, and 1.9 m·s−1; all P &amp;lt; 0.01) following eccentric cycling training.Conclusion: These results demonstrate that 6 weeks of chronic eccentric cycling training was effective in improving walking economy and can be safely administered and tolerated by healthy individuals. Enhancing ambulatory function through eccentric cycling ergometry would be beneficial for both athletic and mobility-limited populations.

Nordic walking training in elderly, a randomized clinical trial. Part II: Biomechanical and metabolic adaptations

BackgroundNordic walking is an attractive method of endurance training. Nevertheless, the biomechanic response due to the additional contribution of using poles in relation to free walking training has been less explored in the elderly. Purpose: This randomized parallel controlled trial aimed to assess the effects of 8 weeks of Nordic walking and free walking training on the walking economy, mechanical work, metabolically optimal speed, and electromyographic activation in elderly.MethodsThirty-three sedentary elderly were randomized into Nordic walking (n = 16) and free walking group (n = 17) with equalized loads. Submaximal walking tests were performed from 1 to 5 km h−1 on the treadmill.ResultsWalking economy was improved in both free and Nordic walking groups (x2 4.91, p = 0.014) and the metabolically optimal speed was increased by approximately 0.5 km h−1 changing the speed-cost profile. The electromyographic activation in lower and upper limbs, pendular recovery, and total, external, and internal mechanical work remained unchanged (p > 0.05). Interestingly, the internal mechanical work associated with arm movement was higher in the Nordic walking group than in the free walking group after training, while the co-contraction from upper limb muscles was reduced similarly to both groups.ConclusionsEight weeks of Nordic walking training effectively improved the walking economy and functionality as well as maintained the gait mechanics, similar to free walking training in elderly people. This enhancement in the metabolic economy may have been mediated by a reduction in the co-contraction from upper limb muscles.Trial registrationClinicalTrails.gov NCT03096964

Ankle Exoskeleton Assistance Can Improve Over-Ground Walking Economy in Individuals With Cerebral Palsy.

Individuals with neuromuscular impairment from conditions like cerebral palsy face reduced quality of life due to diminishing mobility and independence. Lower-limb exoskeletons have potential to aid mobility, yet few studies have investigated their use during over-ground walking - an exercise that may contribute to our understanding of potential benefit in free-living settings. The goal of this study was to determine the potential for adaptive plantar-flexor assistance from an untethered ankle exoskeleton to improve over-ground walking economy and speed. Six individuals with cerebral palsy completed three consecutive daily over-ground training sessions to acclimate to, and tune, assistance. During a final assessment visit, metabolic cost, walking speed, and soleus electromyography were collected for baseline, unpowered, low, training-tuned, and high assistance conditions. Compared to each participant's baseline condition, we observed a 3.9 ± 1.9% (p = 0.050) increase in walking speed and a 22.0 ± 4.5% (p = 0.002) reduction in soleus activity with training-tuned assistance; metabolic cost of transport was unchanged (p = 0.130). High assistance resulted in an 8.5 ± 4.0% (p = 0.042) reduction in metabolic cost of transport, a 6.3 ± 2.6% (p = 0.029) increase in walking speed, and a 25.0 ± 4.0% (p < 0.001) reduction in soleus activity. Improvement in exoskeleton-assisted walking economy was related to pre-training baseline walking speed ( [Formula: see text], p = 0.001); the slower and more impaired participants improved the most. Energy cost and preferred walking speed remained generally unchanged for the faster and less impaired participants. These findings demonstrate that powered ankle exoskeletons have the potential to improve mobility-related outcomes for some people with cerebral palsy.

Analysis of Aerobic Power and Swing Characteristics in Young Male Race Walkers

Economical walking is defined by the steady state of oxygen consumption with top speed and technique in competition is one of the most important factors to achieve higher performance for Pedestrians. The technique of race walking which is defined by World Athletics race walking competitions rules 230.54.2 not a naturally obtained human skill as normal walking and running of childhood. The purpose of the study was to analyze the association and relation of race velocity with aerobic capacity and kinematic properties. Top 10 race walkers of 10000m race walk discipline (Men- U 20), from 33^rd National Junior Athletic Championships, Nov, 2017 held at Acharya Nagarjuna University, Vijaywada, A. P. India were digitized as the subject. For kinematic analysis, athletes were recorded as they passed through halfway 4.55 KM at back straight on the 400 m track by using two standard digital HD camcorders (Nikon B700, 60Hz) mounted on rigid tripods 90° angle 4 m away from the track inside & outside where reference volume was 5 m long and 1.5 m high. Whereas to measure Vo₂ Max athletes’ performance were taken as they passed through 1.5 miles or 2414.02 m on the track. The video data were analyzed by using motion analysis software (KINOVEA). Descriptive statistics and Pearson Product Moment Correlation coefficient (<i>p</i><0.05) were employed for statistical calculation. The tabulation of data was done by using the IBM SPSS software. The result of the study showed that the correlation between race performance and VO₂ max was quite high, r (8df) = 0.726. A Strong relationship was found between step length and RW performance, i.e. r (8df) = 0.689. Whereas variables like, flight time, linearity, maximum knee and foot height of swing leg were positively correlated with the walking performance. A high degree positive association was located in the torso and pelvic displacement r = 0.768 & 0.804 respectively. In toe off phase “r” value of knee angle with performance was 0.742 that showed a high degree coefficient of correlation. Whereas at heel contact and mid stance phase a low degree negative correlation found (r = -0.489& -0.406). Most of the calculated “r” values were significant as the critical value of 8 df at 0.05 level is 0.631. Due to the direct association of race walking velocity (Mean = 3.427 m/s & SD = 0.235) with VO₂ max, step length, knee angle, torso & pelvic displacement may be this type of result found indifferent phases. Race walking performance was positively associated with the race walking economy (kinematic and physiologic variables), which implies that the fastest race walkers were more economical than the lesser performers. In relation to RW technique and forward propulsion, displacement of torso and pelvic region observed a significant role.

Heavy Resistance Training in Breast Cancer Patients Undergoing Adjuvant Therapy.

Adjuvant breast cancer therapy may reduce maximal muscle strength, muscle mass, and functional performance. Although maximal strength training (MST) has the potential to counteract this debilitating outcome and is shown to be superior to low- and moderate-intensity strength training, it is unknown if it can elicit effective adaptations in patients suffering treatment-induced adverse side effects. Fifty-five newly diagnosed stage I to III breast cancer patients (49 ± 7 yr) scheduled for adjuvant therapy were randomized to MST or a control group. The MST group performed 4 × 4 repetitions of dynamic leg press at approximately 90% of one-repetition maximum (1RM) twice a week for 12 wk. In the MST group, improvements in 1RM (20% ± 8%; P < 0.001) were accompanied by improved walking economy (9% ± 8%) and increased time to exhaustion during incremental walking (9% ± 8%; both P < 0.01). Moreover, the MST group increased 6-min walking distance (6MWD; 10% ± 7%), and chair rising (30% ± 20%) and stair climbing performance (12% ± 7%; all P < 0.001). All MST-induced improvements were different from the control group (P < 0.01) which reduced their 1RM (9% ± 5%), walking economy (4% ± 4%), time to exhaustion (10% ± 8%), 6MWD (5% ± 5%), chair rising performance (12% ± 12%), and stair climbing performance (6% ± 8%; all P < 0.01). Finally, although MST maintained estimated quadriceps femoris muscle mass, a decrease was observed in the control group (7% ± 10%; P < 0.001). The change in 1RM correlated with the change in walking economy (r = 0.754), time to exhaustion (r = 0.793), 6MWD (r = 0.807), chair rising performance (r = 0.808), and stair climbing performance (r = 0.754; all P < 0.001). Lower-extremity MST effectively increases lower-extremity maximal muscle strength in breast cancer patients undergoing adjuvant therapy and results in improved work economy, functional performance, and maintenance of muscle mass. These results advocate that MST should be considered in breast cancer treatment.

On the simple calculation of walking efficiency without kinematic information for its convenient use

BackgroundSince walking is a daily activity not to require the maximal effort in healthy populations, a very few universal bio-parameters and/or methods have been defined to evaluate individual walking characteristics in those populations. A concept of “economy” is a potential candidate; however, walking economy highly depends on speed, so direct comparisons of economy values are difficult between studies. We investigated whether the vertical component of net walking “efficiency” (Effvert; %) is constant across speed. In that case, direct comparisons of Effvert will be possible between studies or individuals at any voluntary speed.MethodsThirty young male participants walked at eight speeds on the level or ± 5% gradients, providing vertical speeds (vvert). Differences in energy expenditure between level and uphill or downhill gradients (ΔEE) were calculated. The metabolic rate for vertical component (MRvert) was calculated by multiplying ΔEE with body mass (BM). The mechanical power output for vertical component (Pmech) was calculated by multiplying BM, gravitational acceleration, and vvert. Effvert was obtained from the ratio of Pmech to MRvert at each vvert. Delta efficiency (Delta-E; %) was also calculated from the inverse slope of the regression line representing the relationship of Pmech to MRvert.ResultsUpward Effvert was nearly constant at around 35% and downward Effvert ranged widely (49–80%). No significant differences were observed between upward Delta-E (35.5 ± 8.8%) and Effvert at any speeds, but not between downward Delta-E (44.9 ± 12.8%) and Effvert.ConclusionsUpward ΔEE could be proportional to vvert. Upward, but not downward, Effvert should be useful not only for healthy populations but also for clinical patients to evaluate individual gait characteristics, because it requires only two metabolic measurements on the level and uphill gradients without kinematic information at any voluntary speed.Trial registrationUMIN000017690 (R000020501; registered May 26th, 2015, before the first trial) and UMIN000031456 (R000035911; registered Feb. 23rd, 2018, before the first trial).

Combined Aerobic and Resistance Training Increases Stretch- Shortening Cycle Potentiation and Walking Economy in Postmenopausal Women.

PurposeSecondary analyses were performed to test whether combined aerobic and resistance training altered walking economy (i.e., net oxygen uptake) and/or stretch-shortening cycle potentiation (SSCP). A further objective was to determine if walking economy and SSCP were related before or after training.MethodsNinety-two postmenopausal women were enrolled wherein 76 completed 16 weeks of supervised aerobic and resistance training. Participants were randomized to one of three training groups based on frequencies: (a) 1 d⋅wk–1 (n = 23); (b) 2 d⋅wk–1 (n = 30) or; (c) 3 d⋅wk–1 (n = 23). Following assessments were performed at baseline and post-training. Indirect calorimetry was used to measure maximal oxygen uptake () and walking economy (submaximal – resting = net ) during a graded exercise test and steady-state treadmill task, respectively. SSCP was determined by measuring the difference between a concentric (CO) and counter-movement (CM) leg press throw.Results, walking economy, CO and CM velocity were significantly improved (p < 0.05) for all training groups, however; no time by group interactions were observed. Paired t-tests revealed participants exercise training 2 d⋅wk–1 exhibited a significant time effect for SSCP (+0.04 ± 0.09 ms–1; p = 0.03). At baseline, multiple linear regression showed a negative relationship between walking net and SSCP (r = −0.22; p < 0.04) adjusted for relative proportion of . No such relationship was found post-training.ConclusionAmong older postmenopausal women, our results indicate that irrespective of frequency of training, 16 weeks of combined aerobic and resistance exercise training increased ease of walking and economy. Additionally, only participants exercising 2 d⋅wk–1 exhibited significant improvement in SSCP.

Effects of modified aerobic training on muscle metabolism in individuals with peripheral arterial disease: a randomized clinical trial

The primary objective of this study was to compare the effects on muscle metabolism of two types of aerobic training, with and without a load on the lower limbs, in adults with peripheral arterial disease (PAD). A simple blind randomized clinical trial was conducted using two groups: conventional aerobic (CG) and modified aerobic with a load on the lower limbs (MG). Both groups underwent training by walking three times a week over a 12-week period. The ratings of muscle metabolism were determined after a treadmill test with constant velocity and inclination concomitant with the use of near infrared spectroscopy (NIRS). Altogether 40 individuals with PAD (CG = 65.45 ± 10.60 and MG = 63.10 ± 10.54) were included in the study. After the intervention, in both groups, there was a reduction in the relative time to recovery (p = 0.002), an improvement in the re-oxygenation rate (p = 0.017), an increased time of resistance after reaching the lowest muscle oxygen saturation (StO2) (p < 0.001), an increase in the distance walked (p < 0.001), and an improvement of the walking economy relative to StO2 (p < 0.001). After 12 weeks of training, an improvement in the deoxygenation rate was observed in both groups (p = 0.002), but with a greater magnitude in the CG (p = 0.017). Only the CG presented an increase in time to reach the lowest StO2 on the treadmill after the intervention (p = 0.010). The traditional aerobic training was superior to the modified training in relation to the improvement of muscle metabolism in patients with PAD.

Muscle Activation Patterns Correlate With Race Walking Economy in Elite Race Walkers: A Waveform Analysis.

To analyze the association between muscle activation patterns on oxygen cost of transport in elite race walkers over the entire gait waveform. A total of 21 Olympic race walkers performed overground walking trials at 14km·h-1 where muscle activity of the gluteus maximus, adductor magnus, rectus femoris, biceps femoris, medial gastrocnemius, and tibialis anterior were recorded. Race walking economy was determined by performing an incremental treadmill test ending at 14km·h-1. This study found that more-economical race walkers exhibit greater gluteus maximus (P = .022, r = .716), biceps femoris (P = .011, r = .801), and medial gastrocnemius (P = .041, r = .662) activation prior to initial contact and weight acceptance. In addition, during the propulsive and the early swing phase, race walkers with higher activation of the rectus femoris (P = .021, r = .798) exhibited better race walking economy. This study suggests that the neuromuscular system is optimally coordinated through varying muscle activation to reduce the metabolic demand of race walking. These findings highlight the importance of proximal posterior muscle activation during initial contact and hip-flexor activation during early swing phase, which are associated with efficient energy transfer. Practically, race walking coaches may find this information useful in the development of specific training strategies on technique.

Greater Forearm Blood Flow is Associated with Better Walking Economy and Gait Speed in Older Adults

Gait speed decline is a well-established predictor of disability and mortality in older adults. Compromised energetic efficiency (i.e. walking economy) is a strong contributor to gait speed decline, but the underlying mechanisms influencing walking economy are undefined. Impaired vascular function is common with aging and thus may be an important contributor to the development of compromised walking economy and slow gait speed, yet the relationships among blood flow within skeletal muscle, walking economy, and gait speed in older adults are unknown. PURPOSE: To examine the relationship between measured forearm blood flow and (i) walking economy and (ii) gait speed in older men and woman. METHODS: Resting arterial inflow and reactive hyperemic blood flow (RHBF) of the left forearm was measured in 55 participants of the Longitudinal Aging Study at Towson (LAST; 53% male, mean age 70, range 51-91 years) using venous occlusion plethysmography. Walking economy was measured as the average rate of oxygen consumption during the final 2 minutes of a 5 minute standardized treadmill-based walking test at 1.5 mile per hour. Gait speed was assessed during 2.5 minutes of normal-paced walking over a 20-meter course. The association between RHBF and walking economy and RHBF and gait speed was modeled using linear regression, adjusting for age, height, and fat-free mass. Sobel tests were used to assess possible mediating effects. RESULTS: In fully adjusted models, RHBF (mean RHBF: 18.0 ± 5.9 mL•100mL tissue-1•min-1) was negatively associated with oxygen consumption (β = -7.5, p < 0.01), indicating that walking economy was 7.5 mL/min lower for each one-unit increase in blood flow. Gait speed (mean 1.3 ± 0.2 m/s) was positively associated with blood flow (β = 0.01, p = 0.05), indicating that gait speed was 0.01 m/s faster for each one-unit increase in blood flow. Mediation analyses further suggested that blood flow may mediate the association between walking economy and gait speed (p=0.06). CONCLUSION: RHBF is a significant predictor of both walking economy and gait speed in older adults, suggesting that better overall vascular health is related to enhanced walking economy and gait speed. Therefore, interventions aimed at improving vascular health in the aging population may be beneficial in maintaining gait speed and mobility with age.

A Spring in Your Step: Exercise Training Increases Stretch-Shortening Cycle Potentiation and Walking Economy

A Spring in Your Step: Exercise Training Increases Stretch-Shortening Cycle Potentiation and Walking Economy

Over-ground Walking Economy In Hemiparetic Stroke

Over-ground Walking Economy In Hemiparetic Stroke