Scotty J. Butcher

Associations between isokinetic muscle strength, high-level functional performance, and physiological parameters in patients with chronic obstructive pulmonary disease

High-level activities are typically not performed by patients with chronic obstructive pulmonary disease (COPD), which results in reduced functional performance; however, the physiological parameters that contribute to this reduced performance are unknown. The aim of this study was to determine the relationships between high-level functional performance, leg muscle strength/power, aerobic power, and anaerobic power. Thirteen patients with COPD underwent an incremental maximal cardiopulmonary exercise test, quadriceps isokinetic dynamometry (isometric peak torque and rate of torque development; concentric isokinetic peak torque at 90°/sec, 180°/sec, and 270°/sec; and eccentric peak torque at 90°/sec), a steep ramp anaerobic test (SRAT) (increments of 25 watts every 10 seconds), and three functional measures (timed up and go [TUG], timed stair climb power [SCPT], and 30-second sit-to-stand test [STS]). TUG time correlated strongly (P < 0.05) with all muscle strength variables and with the SRAT. Isometric peak torque was the strongest determinant of TUG time (r = −0.92). SCPT and STS each correlated with all muscle strength variables except concentric at 270°/sec and with the SRAT. The SRAT was the strongest determinant of SCPT (r = 0.91), and eccentric peak torque at 90°/sec was most significantly associated with STS (r = 0.81). Performance on the SRAT (anaerobic power); slower-velocity concentric, eccentric, and isometric contractions; and rate of torque development are reflected in all functional tests, whereas cardiopulmonary exercise test performance (aerobic power) was not associated with any of the functional or muscle tests. High-level functional performance in patients with COPD is associated with physiological parameters that require high levels of muscle force and anaerobic work rates.

Relationship between ventilatory constraint and muscle fatigue during exercise in COPD

Dynamic hyperinflation and leg muscle fatigue are independently associated with exercise limitation in patients with chronic obstructive pulmonary disease (COPD). The aims of the present study were to examine 1) the relationship between these limitations and 2) the effect of delaying ventilatory limitation on exercise tolerance and leg muscle fatigue. In total, 11 patients with COPD (with a forced expiratory volume in one second of 52% predicted) completed two cycling bouts breathing either room air or heliox, and one bout breathing heliox but stopping at room air isotime. End-expiratory lung volume (EELV), leg muscle fatigue and exercise time were measured. On room air, end-exercise EELV was negatively correlated with leg fatigue. Heliox increased exercise time (from 346 to 530 s) and leg fatigue (by 15%). At isotime, there was no change in leg fatigue, despite a reduction in EELV compared with end-exercise, in both room air and heliox. The change in exercise time with heliox was best correlated with room air leg fatigue and end-inspiratory lung volume. Patients with chronic obstructive pulmonary disease who had greater levels of dynamic hyperinflation on room air had less muscle fatigue. These patients were more likely to increase exercise tolerance with heliox, which resulted in greater leg muscle fatigue.

Therapeutic Singing as an Adjunct for Pulmonary Rehabilitation Participants With COPD: Outcomes of a Feasibility Study

In spite of optimized medical management, many individuals living with chronic obstructive pulmonary disease (COPD) experi- ence distressing and disabling symptoms such as breathlessness and poor quality of life. Novel interventions, such as therapeutic singing, hold promise of ameliorating these inhibiting symptoms. This feasibility study compared the outcomes of an 8-week therapeutic singing program conducted by an accredited music therapist for 14 individuals with advanced COPD who attended a pulmonary rehabilitation program targeted to address symptoms with 5 individuals receiving usual care. While the program was enthusiastically and positively endorsed by participants, we did not find improvements in health-related quality of life, exercise capacity, or perceptions of illness for participants in the singing program compared to those receiving usual care. Further studies on optimal duration and intensity of therapeutic singing programs, as well as evaluation of psychological and quality of life specif- ically related to social interaction, are needed to build the evidence-based practices related to such programs. Keywords

Do physiological measures predict selected CrossFit(®) benchmark performance?

Purpose CrossFit® is a new but extremely popular method of exercise training and competition that involves constantly varied functional movements performed at high intensity. Despite the popularity of this training method, the physiological determinants of CrossFit performance have not yet been reported. The purpose of this study was to determine whether physiological and/or muscle strength measures could predict performance on three common CrossFit “Workouts of the Day” (WODs). Materials and methods Fourteen CrossFit Open or Regional athletes completed, on separate days, the WODs “Grace” (30 clean and jerks for time), “Fran” (three rounds of thrusters and pull-ups for 21, 15, and nine repetitions), and “Cindy” (20 minutes of rounds of five pull-ups, ten push-ups, and 15 bodyweight squats), as well as the “CrossFit Total” (1 repetition max [1RM] back squat, overhead press, and deadlift), maximal oxygen consumption (VO2max), and Wingate anaerobic power/capacity testing. Results Performance of Grace and Fran was related to whole-body strength (CrossFit Total) (r=−0.88 and −0.65, respectively) and anaerobic threshold (r=−0.61 and −0.53, respectively); however, whole-body strength was the only variable to survive the prediction regression for both of these WODs (R2=0.77 and 0.42, respectively). There were no significant associations or predictors for Cindy. Conclusion CrossFit benchmark WOD performance cannot be predicted by VO2max, Wingate power/capacity, or either respiratory compensation or anaerobic thresholds. Of the data measured, only whole-body strength can partially explain performance on Grace and Fran, although anaerobic threshold also exhibited association with performance. Along with their typical training, CrossFit athletes should likely ensure an adequate level of strength and aerobic endurance to optimize performance on at least some benchmark WODs.

Investigation of supraspinatus muscle architecture following concentric and eccentric training

OBJECTIVES To investigate the effects of concentric or eccentric abduction strength training on supraspinatus fiber bundle architecture and strength. DESIGN A pre-post single-subject design. METHODS Thirteen participants were randomized to concentric (n=6) or eccentric (n=7) training groups. Participants completed an eight week shoulder abduction training program in the scapular plane using an isokinetic dynamometer. Resistance training, requiring maximal effort on contraction, consisted of 4 sets of 8 reps at 60°/s in weeks 1-4, and 6 sets of 6 reps at 60°/s in weeks 5-8 with a frequency of 3×/week. Primary outcome measures included fiber bundle length, pennation angle, and muscle thickness of supraspinatus and these were quantified using ultrasound. Secondary outcome measures included isometric, eccentric and concentric abduction strength and these were evaluated using the isokinetic dynamometer. RESULTS Mean fiber bundle length in the relaxed (p=0.033) and contracted (p=0.036) states significantly decreased with concentric training but remained unchanged with eccentric training. A significant increase in pennation angle, muscle thickness, and peak torque were found with training but no significant differences were detected between concentric and eccentric groups. CONCLUSIONS Training mode has a significant impact on fiber bundle length changes of the supraspinatus. Eccentric training of shoulder abduction leads to similar strength gains as concentric, but it may also have the added advantages of maintaining fiber bundle lengths and promoting tendon healing. Study is needed to confirm fiber bundle changes in a clinical population which would further support the use of eccentric abduction strength training in rehabilitation settings.

Multimodal high-intensity interval training increases muscle function and metabolic performance in females

High-intensity interval training (HIIT) is a time-efficient method of improving aerobic and anaerobic power and capacity. In most individuals, however, HIIT using modalities such as cycling, running, and rowing does not typically result in increased muscle strength, power, or endurance. The purpose of this study is to compare the physiological outcomes of traditional HIIT using rowing (Row-HIIT) with a novel multimodal HIIT (MM-HIIT) circuit incorporating multiple modalities, including strength exercises, within an interval. Twenty-eight recreationally active women (age 24.7 ± 5.4 years) completed 6 weeks of either Row-HIIT or MM-HIIT and were tested on multiple fitness parameters. MM-HIIT and Row-HIIT resulted in similar improvements (p < 0.05 for post hoc pre- vs. post-training increases for each group) in maximal aerobic power (7% vs. 5%), anaerobic threshold (13% vs. 12%), respiratory compensation threshold (7% vs. 5%), anaerobic power (15% vs. 12%), and anaerobic capacity (18% vs. 14%). The MM-HIIT group had significant (p < 0.01 for all) increases in squat (39%), press (27%), and deadlift (18%) strength, broad jump distance (6%), and squat endurance (280%), whereas the Row-HIIT group had no increase in any muscle performance variable (p values 0.33-0.90). Post-training, 1-repetition maximum (1RM) squat (64.2 ± 13.6 vs. 45.8 ± 16.2 kg, p = 0.02), 1RM press (33.2 ± 3.8 vs. 26.0 ± 9.6 kg, p = 0.01), and squat endurance (23.9 ± 12.3 vs. 10.2 ± 5.6 reps, p < 0.01) were greater in the MM-HIIT group than in the Row-HIIT group. MM-HIIT resulted in similar aerobic and anaerobic adaptations but greater muscle performance increases than Row-HIIT in recreationally active women.

Test-Retest Reliability and Physiological Responses Associated with the Steep Ramp Anaerobic Test in Patients with COPD

The Steep Ramp Anaerobic Test (SRAT) was developed as a clinical test of anaerobic leg muscle function for use in determining anaerobic power and in prescribing high-intensity interval exercise in patients with chronic heart failure and Chronic Obstructive Pulmonary Disease (COPD); however, neither the test-retest reliability nor the physiological qualities of this test have been reported. We therefore, assessed test-retest reliability of the SRAT and the physiological characteristics associated with the test in patients with COPD. 11 COPD patients (mean FEV1 43% predicted) performed a cardiopulmonary exercise test (CPET) on Day 1, and an SRAT and a 30-second Wingate anaerobic test (WAT) on each of Days 2 and 3. The SRAT showed a high degree of test-retest reliability (ICC = 0.99; CV = 3.8%, and bias 4.5 W, error −15.3–24.4 W). Power output on the SRAT was 157 W compared to 66 W on the CPET and 231 W on the WAT. Despite the differences in workload, patients exhibited similar metabolic and ventilatory responses between the three tests. Measures of ventilatory constraint correlated more strongly with the CPET than the WAT; however, physiological variables correlated more strongly with the WAT. The SRAT is a highly reliable test that better reflects physiological performance on a WAT power test despite a similar level of ventilatory constraint compared to CPET.

The Physiologic Effects of an Acute Bout of Supramaximal High-Intensity Interval Training Compared with a Continuous Exercise Bout in Patients with COPD

This study compared physiological responses and work performed during a supramaximal high-intensity interval exercise training session (HIIT) and a constant work rate (CWR) exercise session. Fourteen patients with COPD (mean FEV1   % predicted (±SD)) completed an incremental cardiopulmonary exercise test (CPET) and a steep ramp anaerobic test (SRAT) and then two exercise bouts to symptom limitation on separate days, in random order: (1) a CWR trial at 80% of CPET peak work rate (mean  W) and (2) a HIIT trial using repeats of 30 s at 70% of SRAT peak work rate (mean  W) followed by 90 s at 20% of CPET peak work rate. Subjects ceased exercise primarily due to dyspnea for both HIIT and CWR (64% vs. 57%, resp.). End-exercise , HR, dyspnea, and leg fatigue were similar between the two exercise protocols. Average work rate was lower in HIIT than CWR (32 vs. 63 W, ); however, subjects performed HIIT longer (542 vs. 202 s, ) and for greater total work (23.3 vs. 12.0 kJ, ). The supramaximal HIIT protocol was well tolerated and demonstrated similar maximal physiologic responses to constant work rate exercise, but with greater leg muscle work performed and greater peak exercise intensity.

The Effect of Set Up Position on EMG Amplitude, Lumbar Spine Kinetics, and Total Force Output During Maximal Isometric Conventional-Stance Deadlifts

The purpose of this study was to examine the biomechanical differences between two set up variations during the isometric initiation of conventional barbell deadlifts (DL): Close-bar DL (CBDL), where the bar is positioned above the navicular, and far-bar DL (FBDL), where the bar is placed above the 3rd metatarsophalangeal joint. A cross-sectional, randomized, within-participant pilot study was used. Experienced powerlifters and weightlifters (n = 10) performed three individual isometric pulls of the initiation of both conditions. The CBDL resulted in lower tibia and knee angles and greater pelvis and torso angles than the FBDL (p < 0.05), as well as greater electromyography (EMG) activity in the biceps femoris and upper lumbar erector spinae, but lower activity in the vastus lateralis, and a lower knee extensor moment (p < 0.05). There were no statistical differences for ground reaction force, joint reaction lumbar shear and compression forces between the two conditions. Despite the differences in pelvis and torso angles between lifting conditions, the internal joint net moment, internal shear forces, and internal compressive forces were not different between the two lifting styles. The CBDL set up also resulted in greater posterior chain (hamstrings and erector spine) EMG amplitude, whereas the FBDL set up resulted in more anterior chain (quadriceps) amplitude. Lifters and coaches may choose either deadlift style, according to preferences or training goals, without concern for differences in lumbar spinal loading.

Physical Activity and Sedentary Behaviour of Master of Physical Therapy Students: An Exploratory Study of Facilitators and Barriers

Purpose: A full 85% of Canadians fail to meet physical activity (PA) guidelines, and 69% report being sedentary. Physical therapists are uniquely positioned to promote an active lifestyle; thus, we explored the PA and sedentary behaviour (SB) of Master of Physical Therapy (MPT) students as well as the associated facilitators and barriers. Methods: We used a mixed-methods approach, accelerometry and photovoice (a focus group discussion in which participants discussed self-selected photographs). Accelerometer data were used to quantify PA (light, moderate, and vigorous) and SB. Thematic analysis of the focus group discussion was informed by the socio-ecological model. Results: A total of 26% of participants met national PA guidelines, and mean daily sedentary time for participants was 670.7 (SD 34.4) minutes. Photovoice analysis revealed four main themes related to the facilitators of and barriers to PA and SB: (1) priorities and life balance, (2) commitment and accountability, (3) environment, and (4) MPT programming. Conclusions: A full 74% of participants did not meet the recommended PA guidelines; this is concerning given their immanent roles as health care professionals. Physical therapists are well prepared to prescribe PA to clients. Not only do MPT students need competencies in prescribing PA and exercise, but they may also need to be supported in meeting PA guidelines themselves and limiting SB throughout their studies.