Results of a feasibility and initial efficacy clinical trial of a high-intensity interval training program using adaptive equipment in persons with multiple sclerosis who have walking disability.

BACKGROUND: High intensity interval training (HIIT) has been identified as potential stimulus for eliciting health-promoting physical activity in an efficient manner among persons with multiple sclerosis (MS). The current study aimed to examine the feasibility and initial efficacy of a 12-week HIIT program using a recumbent stepper (RSTEP) in persons with MS who have walking disability. Feasibility outcomes of interest included process (i.e., recruitment, adherence, and retention rates), resource (i.e., time and monetary costs), management (i.e., data management and safety reporting assessment), and science (i.e., safety, burden, and treatment effect assessment). We hypothesized that 12-weeks of HIIT will be feasible via meeting a priori benchmarks in process, resource, management, and scientific outcomes. The efficacy outcomes of interest included changes in aerobic fitness, physical activity, walking, upper arm function, cognition, fatigue, and depressive symptoms. We hypothesized that 12 weeks of HIIT would result in improvements in aerobic capacity, walking, upper arm function, cognition, fatigue, and depression. METHODS: A pre-post clinical trial design was applied. Participants (N = 16) were recruited and enrolled in the 12-week RSTEP HIIT program who met the following inclusion criteria: age ≥18 years, self-reported diagnosis of MS, Patient Determined Disability Steps scale score 3.0-7.0, relapse free in past 30 days, willing to visit a University Laboratory for study protocol, asymptomatic status for maximal exercise testing, physician approval, and a self-reported ability to speak, read, and understand English. Measures of efficacy outcomes of interest included Six Minute Walk Test (6MW), Timed 25 Foot Walk Test (T25FW), the Brief International Cognitive Assessment in MS (BICAMS), 9-hole peg test (9-HPT), Expanded Disability Status Scale (EDSS), Fatigue Severity Survey (FSS), Hospital Anxiety and Depression Scale (HADS), Godin Leisure Time Exercise Questionnaire (GLTEQ), Multiple Sclerosis Walking Scale-12 (MSWS-12). Participants completed a graded maximal exercise test for measuring aerobic fitness (VO2peak) and prescription of exercise throughout the intervention. All outcomes were measured at baseline, mid-point (6-weeks), and post-intervention (12-weeks). The intervention involved 12 weeks of supervised, individualized HIIT sessions two times per week using RSTEP. The individual HIIT sessions included 10 cycles of 60 s intervals at the work rate associated with 90 % VO2peak followed by 60 s of active recovery intervals, totaling 20 minutes plus 5-minute warm-up and cool-down periods. Process, resources, management, and scientific feasibility outcomes were examined using descriptive statistics, percentage, and frequency analyses. The efficacy of the intervention was assessed using a 1-factor (Time), repeated measure analysis of variance to identify significant changes over time. RESULTS: Fourteen of 16 participants were retained throughout the full study period and adherence with prescribed exercise sessions was 97 %. Twenty-three staff were comprehensively trained across two sites. There was only one adverse event reported that did not impact participation in the study and overall mean satisfaction rating with the program among participants was 4.7/5. There were statistically significant changes in cognitive processing speed (p = 0.002), GLTEQ (p = 0.005), and MSWS-12 (p = 0.04), but not the other outcomes of fitness, arm function, and walking. Of note, there were large effect sizes noted for peak power output (d = 1.10) and FSS (d = 1.05) despite the lack of statistically significant changes CONCLUSION: Feasibility of a 12-week individualized RSTEP HIIT program was established and participants significantly improved on measures of cognition, physical activity, and walking.

Differences in segmental fat accumulation patterns by sex and ethnicity: An international approach.

Excess fat on the body impacts obesity-related co-morbidity risk; however, the location of fat stores affects the severity of these risks. The purpose of this study was to examine segmental fat accumulation patterns by sex and ethnicity using international datasets. An amalgamated and cross-calibrated dataset of dual x-ray absorptiometry (DXA)-measured variables compiled segmental mass for bone mineral content (BMC), lean mass (LM), and fat mass (FM) for each participant; percentage of segment fat (PSF) was calculated as PSFsegment = (FMsegment/(BMCsegment + LMsegment + FMsegment)) × 100. A total of 30 587 adults (N = 16 490 females) from 13 datasets were included. A regression model was used to examine differences in regional fat mass and PSF. All populations followed the same segmental fat mass accumulation in the ascending order with statistical significance (arms < legs < trunk), except for Hispanic/Latinx males (arms < [legs = trunk]). Relative fat accumulation patterns differed between those with greater PSF in the appendages (Arab, Mexican, Asian, Black, American Caucasian, European Caucasian, and Australasian Caucasian females; Black males) and those with greater PSF in the trunk (Mexican, Asian, American Caucasian, European Caucasian, and Australasian Caucasian males). Greater absolute and relative fat accumulation in the trunk could place males of most ethnicities in this study at a higher risk of visceral fat deposition and associated co-morbidities.

Effect of cross-slope angle on running economy and gait characteristics at moderate running velocity.

PURPOSE: Outdoor running surfaces are designed with a cross-slope, which can alter kinetic and kinematic gait parameters. The purpose of this study was to evaluate running economy, gait characteristics, and muscle activation while running on a surface with cross-slopes similar to those encountered on roads and trails. METHODS: Eleven recreational runners (females n = 6) completed 5-min running trials on a treadmill at 10 km h-1 with cross-slopes of 0, 1.15, 2.29, and 6 deg in a randomized order. RESULTS: There were no significant differences in VO2, HR, RER, or VE across cross-slope conditions. Compared to 0 deg of cross-slope, ground contact time and duty factor increased at 2.29 and 6 deg, with significant decreases in absolute and relative flight times. Rear foot angles increased in the upslope leg at 2.29 and 6 deg cross-slopes and decreased in the downslope leg at 6 deg compared to 0 deg of cross-slope, with differences between legs for the 2.29 and 6 deg conditions. Knee flexion at foot strike increased in the upslope leg at a 6 deg cross-slope. Vastus lateralis, biceps femoris, gastrocnemius, and tibialis anterior activation were not affected by the cross-slope conditions. While cross-slopes up to 6 deg result in changes to some gait kinematics, these effects do not impact running economy at moderate running velocity.

Acute Demands and Recovery From Common Interval Training Protocols.

ABSTRACT: Elmer, DJ, Barron, EN, and Chavez, JL. Acute demands and recovery from common interval training protocols. J Strength Cond Res 35(11): 3041-3049, 2021-The definition of interval training is quite broad, with no accepted procedure for classifying protocols with different workloads and work and recovery interval times. In addition, little is known about the differences in training load and recovery from common interval protocols. The purpose of this study was to evaluate the differences in acute physiological demands and perceived difficulty between 3 common interval training protocols and a moderate, continuous exercise session. Eight subjects completed the training sessions on a cycle ergometer in a randomized order, with at least 1 week between sessions: 30-second/4-minute, 1-minute/1-minute, 4-minute/3-minute, and a 45-minute continuous session. Metabolic variables were measured throughout exercise and 30 minutes of recovery. Training impulse (TRIMP), session-RPE, and RPE-training load were also measured. There were significant differences between protocols, including between interval training protocols, for average V̇o2 (p < 0.001) and heart rate (HR) (p = 0.02), total O2 consumption (p < 0.001), peak lactate (p < 0.001), TRIMP (p = 0.02), session-RPE (p = 0.01), and RPE-training load (p < 0.001). There were no significant differences between interval training protocols for peak V̇o2 or peak HR attained during exercise. There were also no differences in V̇o2 or HR after 5 or 30 minutes of recovery. Blood lactate was only significantly higher after 30 minutes of recovery from the 30-second/4-minute compared with the 4-minute/3-minute protocol (p = 0.001) and the 45-minute session (p < 0.001). These findings show a range of differences in acute physiological demands and perceptions from interval training protocols, which should be accounted for when planning training sessions or research studies or when interpreting past research.

Feasibility and initial efficacy of a high-intensity interval training program using adaptive equipment in persons with multiple sclerosis who have walking disability: study protocol for a single-group, feasibility trial.

BACKGROUND: There is considerable evidence for the efficacy of moderate-intensity continuous exercise benefitting clinically relevant outcomes in persons with multiple sclerosis (MS). However, persons with MS who have walking disability (pwMS-wd) are severely deconditioned and may achieve superior benefits by engaging in high-intensity interval training (HIIT), especially while utilizing adaptive equipment, such as recumbent arm/leg stepping (RSTEP). The proposed study will assess the feasibility of a 12-week, RSTEP HIIT program in pwMS-wd. The secondary aim will examine changes in aerobic fitness, physical activity, ambulation, upper arm function, cognition, fatigue, and depression as clinically relevant efficacy outcomes following the 12-week, RSTEP HIIT intervention. METHODS: The study will recruit 15 pwMS-wd. Feasibility will be measured via process, resource, management, and scientific outcomes throughout the entirety of the research study. The secondary, clinically relevant outcomes will consist of a neurological exam, aerobic capacity, physical activity, ambulation, cognition, upper arm function, fatigue, and depression. Outcomes will be assessed at baseline (T1), midpoint (T2, following 6 weeks), and post-intervention (T3, following 12 weeks). The intervention will involve 12 weeks of supervised, individualized HIIT sessions two to three times per week. The individual HIIT sessions will each involve 10 cycles of 60-s intervals at the wattage associated with 90% VO2peak followed by 60 s of active recovery intervals at 15 W, totaling 20 min in length plus 5-min warm-up and cool-down periods. DISCUSSION: The feasibility design of the proposed study will provide experience and preliminary data for advancing towards a proof-of-concept study comparing HIIT to moderate-intensity continuous RSTEP for improving clinically relevant outcomes in a randomized control trial design. The results will be disseminated via manuscripts for publication and a report for distribution among the National Multiple Sclerosis Society. TRIAL REGISTRATION: ClinicalTrials.gov NCT04416243 . Retrospectively registered on June 4, 2020.

Sequential Pulse Compression's Effect on Blood Flow in the Lower-Extremity.

CONTEXT: Several interventions are available to reduce the intensity and duration of the unwanted effects (eg, muscle soreness) associated with physical activity, such as massage, compression garments, and sequential pulse compression (SPC). Such interventions aim to increase blood flow to alleviate symptoms. However, there is a lack of evidence to support the use of SPC to alter total hemoglobin concentration (THb) in active individuals. OBJECTIVE: To examine the acute effects of a single session of SPC on hemoglobin concentration compared with a control condition. DESIGN: Single cohort, crossover design. PARTICIPANTS: Thirty-four physically active and healthy participants (females = 12 and males = 22) completed the study. INTERVENTIONS: The authors randomly assigned participants to first receive the experimental (SPC) or control condition. Measures were recorded precondition and postcondition. Participants returned to the laboratory to complete the second condition ≥24 hours after the first condition. MAIN OUTCOME MEASURES: Relative changes in THb, deoxygenated hemoglobin, and oxygenated hemoglobin measures were recorded using near-infrared spectroscopy placed on the muscle belly of the medial gastrocnemius of the dominant limb. RESULTS: SPC significantly increased THb (P < .001, d = 0.505) and oxygenated hemoglobin (P < .001, d = 0.745) change scores compared with the control condition. No statistical difference in deoxygenated hemoglobin change scores was found between the SPC and control conditions, but a medium effect size suggests potential biological significance (P = .06, d = 0.339). CONCLUSIONS: Overall, SPC increases THb to the lower-extremity and may be a viable option in the management of muscle soreness related to physical activity.

Respiratory Rate Threshold Accurately Estimates the Second Lactate Threshold.

PURPOSE: The modified Dmax method can accurately determine the second lactate threshold (LT2), which is valuable for predicting aerobic performance and prescribing exercise. The purpose of this study is to determine if the modified Dmax method can accurately find thresholds in VE (VT2), VCO2 (VCO2T), RER (RERT), and RR (RRT) to estimate LT2. METHODS: Forty-one participants (females n=23, males n=18) completed an incremental exercise test to determine LT2, VT2, VCO2T, RERT, RRT, and blood lactate=4 mmol/L (La4). RESULTS: VT2 and RRT were strongly correlated with VO2 and HR at LT2, with very small bias and limits of agreement, indicating that VT2 and RRT provide accurate estimates of LT2 (VO2 at VT2-LT2 mean difference=0.37±1.91 ml/kg/min, p=0.95; HR at VT2-LT2 mean difference=0.25±2.58 bpm, p=0.99; VO2 at RRT-LT2 mean difference 0.26±2.11 ml/kg/min, p=0.99; HR at RRT-LT mean difference 0.44±3.31 bpm, p=0.99). VCO2T, RERT, and La4 were either accurate for VO2 or HR estimates of LT2, but not both. CONCLUSIONS: VT2 and RRT provide accurate estimates of LT2 using the modified Dmax method. There is the potential to use RRT in developing field tests to estimate LT2 in practical settings.

Evaluation of Performance Improvements After Either Resistance Training or Sprint Interval-Based Concurrent Training.

Laird IV, RH, Elmer, DJ, Barberio, MD, Salom, LP, Lee, KA, and Pascoe, DD. Evaluation of performance improvements after either resistance training or sprint interval-based concurrent training. J Strength Cond Res 30(11): 3057-3065, 2016-The purpose of this investigation was to examine the effects of concurrent sprint interval and resistance training (CST) vs. resistance training (RT) on measures of strength, power, and aerobic fitness in recreationally active women. Twenty-eight women (20.3 ± 1.7 years; 63.0 ± 9.1; 51.1 ± 7.1 1 repetition maximum (1-RM) back squat (kg); V[Combining Dot Above]O2max: 35.4 ± 4.1 ml·kg·min) were recruited to complete an 11-week training program. Participants were matched-pair assigned to CST or RT cohorts after preliminary testing, which consisted of 1-RM back squats, maximal isometric squats, anaerobic power evaluations, and maximal oxygen consumption. All subjects trained 3 days per week with sprint-interval training occurring at least 4 hours after RT in the CST cohort. Both CST and RT resulted in significant improvements (p ≤ 0.05) in the 1-RM back squat (37.5 ± 7.8; 40.0 ± 9.6 kg), maximal isometric force (55.7 ± 51.3; 53.7 ± 36.7 kg), average peak anaerobic power testing (7.4 ± 6.2; 7.6 ± 6.4%), and zero-incline treadmill velocity, resulting in maximal oxygen consumption (1.8 ± 0.6; 0.8 ± 0.6 km·h). Only zero-incline treadmill velocity demonstrated a group-by-time interaction with a greater improvement after CST (p < 0.01). Rate of force development was not altered in either group. Results provide no evidence of interference to the adaptive process by CST. Coaches desiring improvements in strength, power, and endurance may want to evaluate how spring and high-intensity interval training might supplement programs already in place.

Inflammatory, lipid, and body composition responses to interval training or moderate aerobic training.

PURPOSE: The goal of this study was to compare the effect of work- and duration-matched interval training (HIIT) versus moderate aerobic endurance training (ET) on acute and chronic inflammation, along with changes in the lipid profile, to determine which may be more beneficial for improving cardiovascular health. METHODS: Twelve sedentary males (maximal oxygen consumption = 41.6 ± 5.4 mL kg(-1) min(-1)) completed 8 weeks of aerobic interval training or moderate aerobic training, with variables including C-reactive protein (CRP) for chronic inflammation, interleukin-6 (IL-6) response for the acute inflammatory response, plasma concentrations of high-density lipoprotein (HDL), total cholesterol (TC), triglycerides (TRG), and low-density lipoprotein, and body composition measured before and after the training period. RESULTS: HIIT decreased plasma TRG from 92 ± 32 to 61 ± 12 mg dL(-1), which was significantly different from ET, while ET improved the TC:HDL ratio from 4.67 ± 0.85 to 4.07 ± 0.96 and reduced the percentage of android fat from 36.78 ± 9.60 to 34.18 ± 11.39 %. Neither training protocol resulted in an acute IL-6 response on the first nor the last day of exercise, a change in chronic levels of CRP, or a significant increase in HDL, despite previous research finding these changes. CONCLUSIONS: It seems that in order to maximize the health outcomes from physical activity, both HIIT and ET should be included. The acute inflammatory response and reductions in chronic inflammation resulting from exercise training may not be as common as the literature suggests.