Biomechanical analysis of trunk and lower limbs during stair activity in patients with scoliosis.

Staircases are a frequently encountered obstacle in daily life, requiring individuals to navigate ascending and descending movements that place additional demands on the trunk and lower limbs compared to walking on level surfaces. Therefore, it is crucial to examine the biomechanical characteristics of the trunk and lower limbs in individuals with scoliosis during stair activity. The aim of this study was to investigate the biomechanical differences in trunk and lower limbs during daily stair activities between patients with scoliosis and a healthy population. Additionally, the study aimed to explore the relationship between trunk abnormalities and lower limb biomechanics, providing a clinical and objective assessment basis for scoliosis. The Qualisys system, based in Gothenburg, Sweden, was employed for data collection in this study, with a sampling frequency of 150 Hz. It captured the kinematics of the trunk and lower limbs, as well as the kinetics of the lower limbs during stair ascent and descent for both the 28 individuals with scoliosis and the 28 control participants. The results indicate that scoliosis patients demonstrated significantly higher asymmetry compared to the control group in various measures during ascent and decent. These include different parts of kinematics and kinetics. Scoliosis patients demonstrate noticeable variations in their movement patterns compared to the healthy population when engaging in stair activities. Specifically, during stair ascent, scoliosis patients exhibit a seemingly more rigid movement pattern, whereas descent is characterized by an unstable pattern.

The effects of various stair-climbing exercises on functional mobility and trunk muscle activation in community-dwelling older adults: A pilot randomized controlled trial.

BACKGROUND: Stair-climbing (SC) is an essential daily life skill, and stair-climbing exercise (SCE) serves as a valuable method for promoting physical activity in older adults. This study aimed to compare the impact of SCEs with heel contact (HC) and heel off (HO) during SC on functional mobility and trunk muscle (TM) activation amplitudes in community-dwelling older adults. METHODS: In the pilot randomized controlled trial, participants were randomly allocated to either the HC group (n = 17; mean age 75.9 ± 6.3 years) or the HO group (n = 17; mean age 76.5 ± 4.6 years). The HC participants performed SCE with the heel of the ankle in contact with the ground, while the HO participants performed SCE with the heel of the ankle off the ground during SC. Both groups participated in progressive SCE for one hour per day, three days per week, over four consecutive weeks (totaling 12 sessions) at the community center. We measured timed stair-climbing (TSC), timed up and go (TUG), and electromyography (EMG) amplitudes of the TMs including rectus abdominis (RA), external oblique (EO), transverse abdominus and internal oblique abdominals (TrA-IO), and erector spinae (ES) during SC before and after the intervention. RESULTS: Both groups showed a significant improvement in TSC and TUG after the intervention (P < .01, respectively), with no significant difference between the groups. There was no significant difference in the EMG activity of the TMs between the groups after the intervention. The amplitude of TMs significantly decreased after the intervention in both groups (P < .01, respectively). CONCLUSION: Both SCE methods could improve balance and SC ability in older adults while reducing the recruitment of TMs during SC. Both SCE strategies are effective in improving functional mobility and promoting appropriate posture control during SC in older adults.

Transformable Quadruped Wheelchairs Capable of Autonomous Stair Ascent and Descent.

Despite advancements in creating barrier-free environments, many buildings still have stairs, making accessibility a significant concern for wheelchair users, the majority of whom check for accessibility information before venturing out. This paper focuses on developing a transformable quadruped wheelchair to address the mobility challenges posed by stairs and steps for wheelchair users. The wheelchair, inspired by the Unitree B2 quadruped robot, combines wheels for flat surfaces and robotic legs for navigating stairs and is equipped with advanced sensors and force detectors to interact with its surroundings effectively. This research utilized reinforcement learning, specifically curriculum learning, to teach the wheelchair stair-climbing skills, with progressively increasing complexity in a simulated environment crafted in the Unity game engine. The experiments demonstrated high success rates in both stair ascent and descent, showcasing the wheelchair's potential in overcoming mobility barriers. However, the current model faces limitations in tackling various stair types, like spiral staircases, and requires further enhancements in safety and stability, particularly in the descending phase. The project illustrates a significant step towards enhancing mobility for wheelchair users, aiming to broaden their access to diverse environments. Continued improvements and testing are essential to ensure the wheelchair's adaptability and safety across different terrains and situations, underlining the ongoing commitment to technological innovation in aiding individuals with mobility impairments.

Examining BMI-knee angle relationship in healthy young adults during stair ambulation using Kinovea® software.

OBJECTIVE: This study explored the correlation between body mass index (BMI) and knee angle during ascending and descending stairs in healthy young adults. The hypothesis was that higher BMI would be associated with altered knee angles during stair ambulation. PATIENTS AND METHODS: Participants' (n = 43) demographic characteristics, including age, height, weight, BMI, leg preference, and thigh lengths, were recorded. Gait parameters, such as cycle duration, stride phase, velocity, and knee angles, were analyzed using Kinovea® software. Inferential statistical tests, including ANOVA, t-tests, and correlation analysis, were performed to explore the relationships and differences between variables. RESULTS: No significant effect of BMI on knee angle was found [ascending stairs: F (2, 40) = 0.75, p = 0.47; descending stairs: F (2, 40) = 0.58, p = 0.56]. However, gait parameters differed significantly, with shorter cycle duration during ascending stairs (M = 4.52 s, SD = 0.76 s) compared to descending stairs (M = 4.72 s, SD = 0.81 s). The stride phase varied across BMI categories [F (2, 40) = 3.82, p < 0.05], with the ideal weight group (M = 47.12%, SD = 3.21%) exhibiting a distinct stride phase. Positive correlations were found between knee angle and thigh length difference during ascending (r = 0.42, p < 0.05) and descending stairs (r = 0.38, p < 0.05). CONCLUSIONS: This study demonstrated that BMI did not significantly affect knee angle during stair ambulation. However, gait parameters such as cycle duration, stride phase, and velocity differed between ascending and descending stairs. The positive correlation between knee angle and thigh length difference suggests that individuals with more significant thigh length differences may exhibit larger knee angles during stair climbing. The findings of this study have clinical implications for rehabilitation programs and the design of assistive devices. Understanding the relationship between BMI, thigh length difference, and knee angle during stair climbing can help clinicians better assess and manage gait abnormalities in individuals navigating stairs.

Effect of age on ankle biomechanics and tibial compression during stair descent.

BACKGROUND: Stress fracture is a concern among older adults, as age-related decrements in ankle neuromuscular function may impair their ability to attenuate tibial compressive forces experienced during daily locomotor tasks, such as stair descent. Yet, it is unknown if older adults exhibit greater tibial compression than their younger counterparts when descending stairs. RESEARCH QUESTION: Do older adults exhibit differences in ankle biomechanics that alter their tibial compression during stair descent compared to young adults, and is there a relation between tibial compression and specific changes in ankle biomechanics? METHODS: Thirteen young (18-25 years) and 13 older (> 65 years) adults had ankle joint biomechanics and tibial compression quantified during a stair descent. Discrete ankle biomechanics (peak joint angle and moment, and joint stiffness) and tibial compression (maximum and impulse) measures were submitted to an independent t-test, while ankle joint angle and moment, and tibial compression waveforms were submitted to an independent statistical parametric mapping t-test to determine group differences. Pearson correlation coefficients (r) determined the relation between discrete ankle biomechanics and tibial compression measures for all participants, and each group. RESULTS: Older adults exhibited smaller maximum tibial compression (p = 0.004) from decreases in peak ankle joint angle and moment between 17 % and 34 % (p = 0.035), and 20-31 % of stance (p < 0.001) than young adults. Ankle biomechanics exhibited a negligible to weak correlation with tibial compression for all participants, with peak ankle joint moment and maximum tibial compression (r = -0.48 ±â€¯0.32) relation the strongest. Older adults typically exhibited a stronger relation between ankle biomechanics and tibial compression (e.g., r = -0.48 ±â€¯0.47 vs r = -0.27 ±â€¯0.52 between peak ankle joint moment and maximum tibial compression). SIGNIFICANCE: Older adults altered ankle biomechanics and decreased maximum tibial compression to safely execute the stair descent. Yet, specific alterations in ankle biomechanics could not be identified as a predictor of changes in tibial compression.

Effects of acute and chronic stair-climbing exercise on metabolic health: A systematic review.

Stair climbing exercise (SE) provides a feasible approach to elevate physical activity, but the effects on metabolic health are unclear. We systematically reviewed the currently available evidence on the effects of SE on fasting and postprandial glycaemia and lipidaemia. Studies were included if they investigated the effects of acute or chronic (at least 2 weeks) SE on fasting and/or postprandial glycaemic (insulin and glucose) and lipidaemic (triacylglycerols and non-esterified fatty acids) responses in healthy, prediabetic or type 2 diabetic adult populations. PubMed, Web of Science and Scopus were searched for eligible studies until July 2022. A total of 25 studies (14 acute and 11 chronic) were eligible for review. Acute bout(s) of SE can reduce postprandial glycaemia in individuals with prediabetes and type 2 diabetes (8 of 9 studies), but not in normoglycemic individuals. The effects of acute SE on postprandial lipidaemic responses and SE training on both fasting and postprandial glycaemia/lipidaemia were unclear. Acute SE may reduce postprandial glucose concentrations in people with impaired glycaemic control, but high-quality studies are needed. More studies are needed to determine the effect of chronic SE training on postprandial glucose and lipid responses, and the acute effects of SE on lipid responses.

The association between stair climbing and modifiable cardiovascular disease risk factors: the Suita Study.

BACKGROUND: Stair climbing is a readily available form of physical activity with potential cardiovascular benefits. This study aimed to investigate the association between stair climbing and numerous modifiable cardiovascular disease (CVD) risk factors. METHODS: In this cross-sectional study, we used data from 7282 Japanese people (30-84 years) residing in Suita City, Osaka. CVD risk factors and stair climbing frequency were assessed during the Suita Study health examination. Logistic regressions were used to calculate the odds ratios (ORs) and 95% confidence intervals (95% CIs) for CVD risk factors across stair climbing frequencies. RESULTS: After adjustment for age, sex, lifestyle, and medical conditions, stair climbing >60% of the time, compared to <20% of the time, was inversely associated with obesity, smoking, physical inactivity, and stress: ORs (95% CIs) = 0.63 (0.53, 0.75), 0.81 (0.69, 0.96), 0.48 (0.41, 0.55), and 0.67 (0.58, 0.78), respectively (p-trends < 0.05). CONCLUSION: Stair climbing was inversely associated with obesity, smoking, physical inactivity, and stress; suggesting a potential role for cardiovascular disease prevention.

Exercise snacks are a time-efficient alternative to moderate-intensity continuous training for improving cardiorespiratory fitness but not maximal fat oxidation in inactive adults: a randomized controlled trial.

The aims of this study were (1) to determine how stair-climbing-based exercise snacks (ES) compared to moderate-intensity continuous training (MICT) for improving cardiorespiratory fitness (CRF), and (2) to explore whether ES could improve maximal fat oxidation rate (MFO) in inactive adults. Healthy, young, inactive adults (n: 42, age: 21.6 ± 2.3 years, BMI: 22.5 ± 3.6 kg·m-2, peak oxygen uptake (VO2peak): 33.6 ± 6.3 mL·kg-1·min-1) were randomly assigned to ES, MICT, or Control. ES (n = 14) and MICT (n = 13) groups performed three sessions per week over 6 weeks, while the control group (n = 15) maintained their habitual lifestyle. ES involved 3 × 30 s "all-out" stair-climbing (6 flight, 126 steps, and 18.9 m total height) bouts separated by >1 h rest, and MICT involved 40 min × 60%-70% HRmax stationary cycling. A significant group × time interaction was found for relative VO2peak (p < 0.05) with ES significantly increasing by 7% compared to baseline (MD = 2.5 mL·kg-1·min-1 (95% CI = 1.2, 3.7), Cohen's d = 0.44), while MICT had no significant effects (MD = 1.0 mL·kg-1·min-1 (-1.1, 3.2), Cohen's d = 0.17), and Control experienced a significant decrease (MD = -1.7 mL·kg-1·min-1 (-2.9, -0.4), Cohen's d = 0.26). MFO was unchanged among the three groups (group × time interaction, p > 0.05 for all). Stair climbing-based ES are a time-efficient alternative to MICT for improving CRF among inactive adults, but the tested ES intervention appears to have limited potential to increase MFO.

Effect of single-radius design on in vivo kinematics during stair activities after total knee arthroplasty.

BACKGROUND: The single-radius design is one of the major total knee arthroplasty (TKA) designs and widely used all over the world. The objective of this study was to compare in vivo kinematics between the anteroposterior (AP) single-radius design with mediolateral (ML) single-radius (Non Restricted Geometry; NRG) and ML dual-radius (Triathlon) during stair activities. METHODS: A total of 21 knees in 18 patients (NRG group: 10 knees in 7 patients, Triathlon group: 11 knees in 11 patients) with a clinically successful posterior stabilized TKA were examined. Under fluoroscopic surveillance, each patient performed stair ascending and descending motions. In vivo kinematics were analyzed using 2D/3D registration technique. The knee flexion angle, rotation angle, varus-valgus angle, AP translation of the femorotibial contact point for both the medial and lateral sides of the knee, and post-cam engagement were evaluated. RESULTS: There were no significant differences between the two groups in rotation angle and AP translation at each flexion angle. Examining the varus-valgus angle, the NRG group showed varus position at an early flexion angle during both stair activities.Post-cam engagement was observed in both groups during both stair activities. The mean flexion angle of engagement in the NRG group, the post of which was located anterior to the Triathlon, was larger than that in the Triathlon group during both stair activities. CONCLUSION: Despite the same AP single-radius TKA, ML single-radius might affect varus motion at an early flexion angle.

Relationship of device measured physical activity type and posture with cardiometabolic health markers: pooled dose-response associations from the Prospective Physical Activity, Sitting and Sleep Consortium.

AIMS/HYPOTHESIS: The aim of this study was to examine the dose-response associations of device-measured physical activity types and postures (sitting and standing time) with cardiometabolic health. METHODS: We conducted an individual participant harmonised meta-analysis of 12,095 adults (mean ± SD age 54.5±9.6 years; female participants 54.8%) from six cohorts with thigh-worn accelerometry data from the Prospective Physical Activity, Sitting and Sleep (ProPASS) Consortium. Associations of daily walking, stair climbing, running, standing and sitting time with a composite cardiometabolic health score (based on standardised z scores) and individual cardiometabolic markers (BMI, waist circumference, triglycerides, HDL-cholesterol, HbA1c and total cholesterol) were examined cross-sectionally using generalised linear modelling and cubic splines. RESULTS: We observed more favourable composite cardiometabolic health (i.e. z score <0) with approximately 64 min/day walking (z score [95% CI] -0.14 [-0.25, -0.02]) and 5 min/day stair climbing (-0.14 [-0.24, -0.03]). We observed an equivalent magnitude of association at 2.6 h/day standing. Any amount of running was associated with better composite cardiometabolic health. We did not observe an upper limit to the magnitude of the dose-response associations for any activity type or standing. There was an inverse dose-response association between sitting time and composite cardiometabolic health that became markedly less favourable when daily durations exceeded 12.1 h/day. Associations for sitting time were no longer significant after excluding participants with prevalent CVD or medication use. The dose-response pattern was generally consistent between activity and posture types and individual cardiometabolic health markers. CONCLUSIONS/INTERPRETATION: In this first activity type-specific analysis of device-based physical activity, ~64 min/day of walking and ~5.0 min/day of stair climbing were associated with a favourable cardiometabolic risk profile. The deleterious associations of sitting time were fully attenuated after exclusion of participants with prevalent CVD and medication use. Our findings on cardiometabolic health and durations of different activities of daily living and posture may guide future interventions involving lifestyle modification.

Concurrent Validity and Reliability of Video-Based Approach to Assess Physical Function in Adults With Knee Osteoarthritis.

OBJECTIVES: The aim of this study was to determine the concurrent validity and reliability of the Osteoarthritis Research Society International recommended performance-based tests delivered by video-based in adults with knee osteoarthritis. METHODS: Thirty-two participants (aged 40-70 years; 15 men) undertook assessments of 4 performance-based tests via both video-based (real-time and recorded) and face-to-face approaches, on the same day. Outcome measures were performance-based test and the number of technical issues encountered. The performance-based tests included the 40-Meter Fast-Paced Walk Test (velocity, m/s), the 30-Second Chair Stand Test (number of repetitions), the Stair Climb Test (time, seconds), and the Timed "Up & Go" Test (time, seconds). The Bland-Altman limit of agreement measures, standard error of measurement (SEM), coefficient of variation (CV), minimal detectable changes, and bias (mean difference) were employed to analyze the concurrent validity between video-based and face-to-face approaches of the performance-based tests. Reliability was measured using intraclass correlation coefficients, CV, and SEM. RESULTS: A high degree of concurrent validity for the Timed "Up & Go" Test (bias = -0.22), the 30-Second Chair Stand Test (bias = -0.22), the Stair Climb Test (bias = -0.31), and the 40-Meter Fast-Paced Walk Test (bias = -0.06) was found. SEM and CV values were within the acceptable level for concurrent validity. There was a high degree of reliability demonstrated for all tests analyzed. Intraclass correlation coefficient measures ranged from 0.95 to 1.00 for intrarater reliability, and from 0.95 to 0.99 for interrater reliability. CONCLUSIONS: Video-based assessment of physical performance tests is a valid and reliable tool for measuring physical function among adults with knee osteoarthritis via Microsoft Teams (Microsoft Corp, Redmond, WA, USA). IMPACT: Video-based assessment is a promising public health tool to measure physical function in adults with knee osteoarthritis.

Effect of Combined Intervention of Yoga and Physiotherapy as Compared to Only Physiotherapy on Lower Limb Muscle Strength, Balance and Range of Motion among Elders with Compromised Stair Climbing in Puducherry - A Parallel Arm Non-Randomized Control Trial.

SUMMARY: The activity of daily living (ADL) related to stair climbing is one of the most compromised ADLs among the elders. It requires good muscle strength, balance, and range of motion (ROM) in the lower limb. We aimed to investigate the effects of Yoga complemented with physiotherapy (Intervention group) compared to only physiotherapy (control group) on lower limb muscle strength, balance, and ROMs among elders with ADL limitation in stair climbing. Sixty-five community-dwelling elders with compromised stair climbing were enrolled. Elders who consented to yoga along with physiotherapy were enrolled in the intervention arm. Data were collected and analyzed following 12 weeks of intervention. Endline assessment showed that the intervention group had more improvement in all test scores and ROMs as compared to the control group, although there were improvements in both arms as compared to baseline. Considering the beneficial effects of both interventions, yoga can be added to gain additional advantages.Trial Registration:Indian Clinical Trials Registry number CTRI/2021/08/035825.

Lower-limb kinematics and kinetics during continuously varying human locomotion.

Human locomotion involves continuously variable activities including walking, running, and stair climbing over a range of speeds and inclinations as well as sit-stand, walk-run, and walk-stairs transitions. Understanding the kinematics and kinetics of the lower limbs during continuously varying locomotion is fundamental to developing robotic prostheses and exoskeletons that assist in community ambulation. However, available datasets on human locomotion neglect transitions between activities and/or continuous variations in speed and inclination during these activities. This data paper reports a new dataset that includes the lower-limb kinematics and kinetics of ten able-bodied participants walking at multiple inclines (±0°; 5° and 10°) and speeds (0.8 m/s; 1 m/s; 1.2 m/s), running at multiple speeds (1.8 m/s; 2 m/s; 2.2 m/s and 2.4 m/s), walking and running with constant acceleration (±0.2; 0.5), and stair ascent/descent with multiple stair inclines (20°; 25°; 30° and 35°). This dataset also includes sit-stand transitions, walk-run transitions, and walk-stairs transitions. Data were recorded by a Vicon motion capture system and, for applicable tasks, a Bertec instrumented treadmill.

Finite element analysis of femoral neck strains during stair ascent and descent.

For older population, a better understanding of the hip joint loading environment is needed for the prevention of hip pain, and the reduction of the stress fractures and fall risks. Using the motion analysis and inverse dynamics methods, combined with musculoskeletal modelling, static optimization, and finite element (FE) femur model, the difference of femoral neck strains between stair ascent vs. descent, young vs. older populations was compared. A two-way repeated-measures MANOVA was applied to test the effect of age and stair direction on the femoral neck strains. The strains at the femoral neck cross-section were greater for stair descent than ascent for both age groups (mostly P = 0.001 to 0006) but there was no difference between age groups. In this study, femoral neck strains represented bone loading environment in more direct ways than joint reaction forces/moments or joint contact forces, the risk of hip pain, falls and stress fractures might be greater during stair descent than ascent. Possible preventative methods to reduce these risks should be developed in the future studies.

Intermittent vibrational stimulation enhances mobility during stair navigation in patients with knee pain.

BACKGROUND: Reduced quadriceps function and proprioception can cause decreased mobility during stair navigation in patients with knee pain. Patients can benefit from interventions to mitigate pain and restore quadriceps function. Activating the somatosensory system via intermittent vibrational stimulation has the potential to improve stair navigation mobility in patients with knee pain by moderating quadriceps inhibition and enhancing proprioception. RESEARCH QUESTION: What are the effects of intermittent vibrational stimulus synchronized to stair ambulation on muscle activity, kinematics, kinetics, and pain using a randomized controlled clinical trial design. METHODS: Thirty-eight patients with knee pain were enrolled into a blinded cross-over study, and twenty-nine patients completed all assessments and analyses. Subjects were randomly assigned sequentially to both an active Treatment A (active) and passive Treatment B (passive) worn at the knee during ambulation for 4 weeks with a 2-week washout period between treatments. RESULTS: Knee pain during stair navigation was significantly reduced only with Treatment A (P = 0.007). During ascent, Treatment A (active) significantly increased vastus lateralis activation (P = 0.01), increased knee flexion moment (P = 0.04) and decreased trunk flexion angles (P = 0.015) between baseline and 4-week follow-up. After using passive Treatment B, there were no significant differences in pain (P = 0.19), knee flexion moment (P = 0.09), and trunk flexion angles (P = 0.23). Changes in muscle function correlated significantly with changes in knee flexion moment and trunk flexion with Treatment A (P < 0.015). Descending differed from ascending in response to Treatment A with significantly decreased knee flexion moment(P = 0.04), hip(P = 0.02) and ankle(P = 0.04) flexion angles. Treatment B significantly reduced hip flexion angles (P = 0.005) but not knee flexion moment (P = 0.85). SIGNIFICANCE: The results of this study suggest that intermittent vibration can improve joint motion and loading during stair navigation by enhancing quadriceps function during stair ascent and improving movement control during stair descent by modifying an adaptive flexed movement pattern in the lower limb.

Implant design affects walking and stair navigation after total knee arthroplasty: a double-blinded randomised controlled trial.

BACKGROUND: Dissimilar total knee arthroplasty implant designs offer different functional characteristics. This is the first work in the literature to fully assess the Columbus ultra-congruent mobile (UCR) system with a rotating platform. METHODS: This is a double-blinded randomised controlled trial, comparing the functional performance of the low congruent fixed (CR DD), ultra-congruent fixed (UC) and UCR Columbus Total Knee Systems. The pre-operative and post-operative functional performance of twenty-four osteoarthritic patients was evaluated against nine control participants when carrying out everyday tasks. Spatiotemporal, kinematic and kinetic gait parameters in walking and stair navigation were extracted by means of motion capture. RESULTS: The UC implant provided better post-operative function, closely followed by the UCR design. However, both the UC and UCR groups exhibited restricted post-operative sagittal RoM (walking, 52.1 ± 4.4° and 53.2 ± 6.6°, respectively), whilst patients receiving a UCR implant did not show an improvement in their tibiofemoral axial rotation despite the bearing's mobile design (walking, CR DD 13.2 ± 4.6°, UC 15.3 ± 6.7°, UCR 13.5 ± 5.4°). Patients with a CR DD fixed bearing showed a statistically significant post-operative improvement in their sagittal RoM when walking (56.8 ± 4.6°). CONCLUSION: It was concluded that both ultra-congruent designs in this study, the UC and UCR bearings, showed comparable functional performance and improvement after TKA surgery. The CR DD group showed the most prominent improvement in the sagittal RoM during walking. TRIAL REGISTRATION: The study is registered under the clinical trial registration number: NCT02422251 . Registered on April 21, 2015.

Both Traditional and Stair Climbing-based HIIT Cardiac Rehabilitation Induce Beneficial Muscle Adaptations.

PURPOSE: There is a lack of knowledge as to how different exercise-based cardiac rehabilitation programming affects skeletal muscle adaptations in coronary artery disease (CAD) patients. We first characterized the skeletal muscle from adults with CAD compared with a group of age- and sex-matched healthy adults. We then determined the effects of a traditional moderate-intensity continuous exercise program (TRAD) or a stair climbing-based high-intensity interval training program (STAIR) on skeletal muscle metabolism in CAD. METHODS: Sixteen adults (n = 16, 61 ± 7 yr), who had undergone recent treatment for CAD, were randomized to perform (3 d·wk-1) either TRAD (n = 7, 30 min at 60%-80% of peak heart rate) or STAIR (n = 9, 3 × 6 flights) for 12 wk. Muscle biopsies were collected at baseline in both CAD and healthy controls (n = 9), and at 4 and 12 wk after exercise training in CAD patients undertaking TRAD or STAIR. RESULTS: We found that CAD had a lower capillary-to-fiber ratio (C/Fi, 35% ± 25%, P = 0.06) and capillary-to-fiber perimeter exchange (CFPE) index (23% ± 29%, P = 0.034) in Type II fibers compared with healthy controls. However, 12 wk of cardiac rehabilitation with either TRAD or STAIR increased C/Fi (Type II, 23% ± 14%, P < 0.001) and CFPE (Type I, 10% ± 23%, P < 0.01; Type II, 18% ± 22%, P = 0.002). CONCLUSION: Cardiac rehabilitation via TRAD or STAIR exercise training improved the compromised skeletal muscle microvascular phenotype observed in CAD patients.

Estimation of ground reaction forces during stair climbing in patients with ACL reconstruction using a depth sensor-driven musculoskeletal model.

BACKGROUND: Although stair ambulation should be included in the rehabilitation of the long-term effects of ACL injury on knee function, the assessment of kinetic parameter in the situation where stair gait can only be established using costly and cumbersome force platforms via conventional inverse dynamic analysis. Therefore, there is a need to develop a practical laboratory setup as an assessment tool of the stair gait abnormalities in lower extremity that arise from an ACL deficiency. RESEARCH QUESTION: Can the use of a single depth sensor-driven full-body musculoskeletal gait model be considered an accurate assessment tool of the ground reaction forces (GRFs) during stair climbing for patients following ACL reconstruction (ACLR) surgery? METHODS: A total of 15 patients who underwent ACLR participated in this study. GRFs data during stair climbing was collected using a custom-built 3-step staircase with two embedded force platforms. A single depth sensor, commercially available and cost effective, was used to obtain participants' depth map information to extract the full-body skeleton information. The AnyBody TM GaitFullBody model was utilized to estimate GRFs attained by 25 artificial muscle-like actuators placed under each foot. Mean differences between the measured and estimated GRFs were compared using paired samples t-tests. The ensemble curves of the GRFs were compared between both approaches during stance phase of the gait cycle. RESULTS: The findings of this study showed that the estimation of the GRFs produced during staircase gait using a depth sensor-driven musculoskeletal model can produce acceptable results when compared to the traditional inverse dynamics modelling approach as an alternative tool in clinical settings for individuals who had undergone ACLR. SIGNIFICANCE: The introduced approach of full-body musculoskeletal modelling driven by a single depth sensor has the potential to be a cost-effective stair gait analysis tool for patients with ACL injury.

Prediction of Balance Perturbations and Falls on Stairs in Older People Using a Biomechanical Profiling Approach: A 12-Month Longitudinal Study.

BACKGROUND: Stair falls are a major health problem for older people, but presently, there are no specific screening tools for stair fall prediction. The purpose of the present study was to investigate whether stair fallers could be differentiated from nonfallers by biomechanical risk factors or physical/psychological parameters and to establish the biomechanical stepping profile posing the greatest risk for a stair fall. METHODS: Eighty-seven older adults (age: 72.1 ± 5.2 years) negotiated an instrumented seven-step staircase and performed a range of physical/psychological tasks. k-Means clustering was used to profile the overall stair negotiation behavior with biomechanical parameters indicative of fall risk as input. Falls and events of balance perturbation (combined "hazardous events") were then monitored during a 12-month follow-up. Cox-regression analysis was performed to examine whether physical/psychological parameters or biomechanical outcome measures could predict future hazardous events. Kaplan-Meier survival curves were obtained to identify the stepping strategy posing a risk for a hazardous event. RESULTS: Physical/psychological parameters did not predict hazardous events and the commonly used Fall Risk Assessment Tool classified only 1/17 stair fallers at risk for a fall. Single biomechanical risk factors could not predict hazardous events on stairs either. On the contrary, two particular clusters identified by the stepping profiling method in stair ascent were linked with hazardous events. CONCLUSION: This highlights the potential of the stepping profiling method to predict stair fall risk in older adults against the limited predictability of single-parameter approaches currently used as screening tools.

Hourly staircase sprinting exercise "snacks" improve femoral artery shear patterns but not flow-mediated dilation or cerebrovascular regulation: a pilot study.

Healthy males (n = 10; age: 24 ± 4 years; body mass index: 24 ± 2 kg·m-2) completed 2 randomized conditions separated by ≥48 h involving 6-8.5 h of sitting with ("stair snacks") and without (sedentary) hourly staircase sprint interval exercise (∼14-20 s each). Resting blood flow and shear rates were measured in the femoral artery, internal carotid artery, and vertebral artery (Duplex ultrasound). Flow-mediated dilation (FMD) was quantified as an index of peripheral endothelial function in the femoral artery. Neurovascular coupling (NVC; regional blood flow response to local increases in cerebral metabolism) was assessed in the posterior cerebral artery (transcranial Doppler ultrasound). Femoral artery hemodynamics were higher following the active trial with no change in the sedentary trial, including blood flow (+32 ± 23% vs. -10 ± 28%; P = 0.015 and P = 0.253, respectively), vascular conductance (+32 ± 27% vs. -15 ± 26%; P = 0.012 and P = 0.098, respectively), and mean shear rate (+17 ± 8% vs. -8 ± 28%; P = 0.004 and P = 0.310, respectively). The change in FMD was not different within or between conditions (P = 0.184). Global cerebral blood flow (CBF), conductance, shear patterns, and NVC were not different within or between conditions (all P > 0.05). Overall, exercise "stair snacks" improve femoral artery blood flow and shear patterns but not peripheral (e.g., FMD) or cerebral (e.g., CBF and NVC) vascular function following prolonged sitting. The study was registered at ClinicalTrials.gov (NCT03374436). Novelty: Breaking up 8.5 h of sitting with hourly staircase sprinting exercise "snacks" improves resting femoral artery shear patterns but not FMD. Cerebral blood flow and neurovascular coupling were unaltered following 6 h of sitting with and without hourly exercise breaks.