Subacromial pain syndrome (SAPS) defined as pain of nontraumatic origin localized around the acromion, is a debilitating, common, and often chronic condition. Among many proposed underlying causes of SAPS, hypoperfusion and hypoxic conditions in and around the tendons may be an intrinsic cause of SAPS. PURPOSE:This study aimed to determine if adding high-intensity aerobic interval training (HIIT) of the rotator cuff to usual care was feasible in SAPS and improved shoulder endurance more than usual care alone, as well as to examine the influence on shoulder pain and disability and the response of tendinous microcirculation after HIIT. METHODS:Twenty-one subjects with chronic SAPS were randomized to two groups: experimental group (EG; n = 13) receiving HIIT in addition to treatment as usual and control group (CG; n = 8) receiving treatment as usual. Before and after 8 wk of exercise therapy, endurance performance was assessed by an incremental abduction exercise of the arm to exhaustion (TTE). Pain and disability was assessed by the shoulder pain and disability index (SPADI). Contrast-enhanced ultrasound of the musculus supraspinatus and tendon was utilized to indicate tendon blood flow. RESULTS:Endurance in the TTE test improved by an estimated 233 s more on average in EG than in CG (P = 0.001; 95% confidence interval, 102 to 363). The SPADI score was reduced 22 points more on average in EG (P = 0.017; 95% confidence interval, -40 to -5). The change from pretest to posttest was significant in EG for both TTE test and SPADI improvement (P < 0.001). EG also experienced less pain during exercise after the intervention compared with CG (P < 0.001). Contrast-enhanced ultrasound indicated an increase in tendinous blood flow in EG (P = 0.019). CONCLUSIONS:HIIT rotator cuff exercise seems to be a feasible intervention in SAPS, increasing endurance performance more than usual care alone.

Subacromial pain syndrome (SAPS) defined as pain of non-traumatic origin localized around the acromion, is a debilitating, common and often chronic condition. Among many proposed underlying causes of SAPS, hypoperfusion and hypoxic conditions in and around the tendons may be an intrinsic cause of SAPS. Exercise therapy with low load is the advocated treatment of choice for SAPS. PURPOUSE: To determine if high intensity aerobic interval training (HIIT) of the rotator cuff was feasible, more effective in improving endurance and reducing pain compared to low intensity exercises. Additionally, to examine the response of tendinous microcirculation following the exercise therapy. METHODS: 21 subjects with chronic SAPS randomized to two groups: HIIT (n=13) and control group (CG) (n=8) was tested before and after 8 weeks of exercise therapy. Endurance performance was assessed by an incremental abduction adduction exercise of the arm to exhaustion (TTE). Contrast enhanced ultrasound (CEUS) of the m. supraspinatus and tendon was utilized to indicate tendon blood flow. Limitations in daily life was assessed by the shoulder pain and disability index (SPADI). RESULTS: Endurance in the TTE-test improved by an estimated 233 seconds more on average in HIIT than in CG (p=0.001, 95%CI: 102 to 363), the change was significant in HIIT (p<0.001), no change was seen in CG. The SPADI score was reduced 22 points more on average in HIIT (p=0.017, 95%CI: -40 to -5). The change from pre to post-test was significant in HIIT(p<0.001), but not in the CG. HIIT also experienced less pain during exercise after the intervention compared to CG (p<0.001). CEUS indicated an increase in tendinous blood flow in the HIIT group (p=0.019), no change was observed in CG. CONCLUSIONS: HIIT rotator cuff exercise appear to be a feasible intervention in SAPS, reducing pain and increasing endurance performance more than exercise with low load. CEUS indicate that HIIT may increase tendon microcirculation, thus abating a potential hypoperfused/ hypoxic state underlying the condition.

Objective: To examine if 8 weeks of high-intensity interval training (HIIT) in addition to standard care would increase and maintain peak oxygen uptake (VO2peak) more than standard care alone in patients with stroke. Design: This was a single-blind, multicenter, parallel group, randomized controlled trial. Setting: Specialized rehabilitation units at 3 Norwegian hospitals. Participants: Participants (N=70), 3 months to 5 years after first-ever stroke, were randomly assigned to the intervention group (n=36) or the control group (n=34); 42% were women, mean age was 57.6 +/- 9.3 years, mean time post stroke was 26.4 +/- 14.5 months. Intervention: The intervention was 8 weeks: 3 times a week with HIIT treadmill training with work periods of 4 x 4 minutes at 85%-95% of peak heart rate interspersed with 3 minutes of active recovery at 50%-70% of peak heart rate. The control group received standard care according to national guidelines. Outcomes: The primary outcome, analyzed by intention-to-treat, was VO2peak measured as liters per minute 12 months after inclusion. Secondary outcome measures were blood pressure and blood profile. Results: Mean baseline VO2peak was 2.63 +/- 1.08 L.min(-1) vs 2.87 +/- 0.71 L.min(-1), while at 12 months VO2peak was 2.70 +/- 1.00 L.min(-1) vs 2.67 +/- 0.76 L.min(-1) (P=.068) in the intervention and control groups, respectively. There was a significant and greater improvement in the intervention group compared with the control group at 12 months in 3 of 6 secondary outcomes from the peak test but no significant differences for blood pressure or blood profile. Conclusions: The HIIT intervention, which was well-tolerated in this sample of well-functioning survivors of stroke, was not superior to standard care in improving and maintaining VO2peak at the 12-month follow-up. However, secondary results from the peak test showed a significant improvement from before to immediately after the intervention. (C) 2020 by the American Congress of Rehabilitation Medicine

Objective: To test whether passive leg cycling (PLC) during arm cycling ergometry (ACE) affects peak oxygen uptake (VO2peak) differently in individuals with spinal cord injury (SCI) at/above the 6th thoracic vertebra (T6) and below T6. Methods: We conducted a cross-sectional study, analyzed by univariate and multivariate regression models. Between- and within-group differences were examined during (a) ACE only, (b) ACE combined with PLC (ACE-PLC), and (c) ACE combined with functional electrical stimulation cycling (FES hybrid). Fifteen SCI subjects were recruited and grouped according to injury level: at/above T6 (SCI-high, n = 8) or below T6 (SCI-low, n = 7). VO2peak tests during ACE only, ACE-PLC, and FES hybrid were performed in random order on separate days. Results: In the SCI-high group, mean (SD) VO2peak was 19% higher during ACE-PLC than during ACE only [21.0 (3.8) vs 17.7 (5.0) mL·kg-1·min-1; p = .002], while VO2peak during FES hybrid cycling was 16% higher than during ACE-PLC [24.4 (4.1) mL·kg-1·min-1; p = .001]. No significant differences among exercise modalities were found for the SCI-low group. Conclusion: Additional training modalities (eg, PLC) during ACE facilitate exercise in SCI-high individuals, but not to the level of the FES hybrid method. Conversely, additional training modalities may not increase training load in SCI-low individuals.

Although aging is typically associated with a decreased efficiency of locomotion, somewhat surprisingly, there is also a reduction in the proportion of less efficient fast-twitch Type II skeletal muscle fibers and subsequently a greater propensity for falls. Maximal strength training (MST), with an emphasis on velocity in the concentric phase, improves maximal strength, the rate of force development (RFD), and work efficiency, but the impact on muscle morphology in the elderly is unknown. Therefore we evaluated force production, walking work efficiency, and muscle morphology in 11 old (72±3years) subjects before and after MST of the legs. Additionally, for reference, the MST-induced morphometric changes were compared with 7 old (74±6years) subjects who performed conventional strength training (CST), with focus on hypertrophy, as well as 13 young (24±2years) controls. As expected, MST in the old improved maximal strength (68%), RFD (48%), and work efficiency (12%), restoring each to a level similar to the young. However, of importance, these MST-induced functional changes were accompanied by a significant increase in the size (66%) and shift toward a larger percentage (56%) of Type II skeletal muscle fibers, mirroring the adaptations in the hypertrophy trained old subjects, with muscle composition now being similar to the young. In conclusion, MST can increase both work efficiency and Type II skeletal muscle fiber size and percentage in the elderly, supporting the potential role of MST as a countermeasure to maintain both physical function and fall prevention in this population.

BACKGROUND:People with stroke have a low peak aerobic capacity and experience increased effort during performance of daily activities. The purpose of this study was to examine test-retest reliability of a portable ergospirometry system in people with stroke during performance of functional activities in a field-test. Secondary aims were to examine the proportion of oxygen consumed during the field-test in relation to the peak-test and to analyse the correlation between the oxygen uptake during the field-test and peak-test in order to support the validity of the field-test.METHODS:With simultaneous measurement of oxygen consumption, participants performed a standardized field-test consisting of five activities; walking over ground, stair walking, stepping over obstacles, walking slalom between cones and from a standing position lifting objects from one height to another. All activities were performed in self-selected speed. Prior to the field-test, a peak aerobic capacity test was performed. The field-test was repeated minimum 2 and maximum 14 days between the tests. ICC2,1 and Bland Altman tests (Limits of Agreement, LoA) were used to analyse test-retest reliability.RESULTS:In total 31 participants (39% women, mean (SD) age 54.5 (12.7) years and 21.1 (14.3) months' post-stroke) were included. The ICC2,1 was ≥ 0.80 for absolute V̇O2, relative V̇O2, minute ventilation, CO2, respiratory exchange ratio, heart rate and Borgs rating of perceived exertion. ICC2,1 for total time to complete the field-test was 0.99. Mean difference in steady state V̇O2 during Test 1 and Test 2 was -0.40 (2.12) The LoAs were -3.75 and 4.51. Participants spent 60.7% of their V̇O2peak performing functional activities. Correlation between field-test and peak-test was 0.689, p = 0.001 for absolute and 0.733, p = 0.001 for relative V̇O2.CONCLUSIONS:This study presents first evidence on reliability of oxygen uptake during performance of functional activities after stroke, showing very good test-retest reliability. The secondary analysis showed that the amount of energy spent during the field-test relative to the peak-test was high and the correlation between the two test was good, supporting the validity of this method.

Objective. To study whether values for peak oxygen uptake (VO2peak) and work economy (WE) at a standardized workload are different when tested by arm crank ergometry (ACE) and wheelchair ergometry (WCE). Methods. Twelve paraplegic men with spinal cord injury (SCI) in stable neurological condition participated in this cross-sectional repeated-measures study. We determined VO2peak and peak power output (POpeak) values during ACE and WCE in a work-matched protocol. Work economy was tested at a standardized workload of 30 Watts (W) for both ACE and WCE. Results. There were no significant differences in VO2peak (mL·kg−1·min−1) between ACE (27.3±3.2) and WCE (27.4±3.8) trials, and a Bland-Altman plot shows that findings are within 95% level of agreement. WE or oxygen consumption at 30 W (VO2-30W) was significantly lower during WCE compared to ACE (P<0.039). Mean (95% CI) POpeak (W) were 130 (111–138) and 100 (83–110) during ACE and WCE, respectively. Conclusion. The findings in the present study support the use of both ACE and WCE for testing peak oxygen uptake. However, WE differed between the two test modalities, meaning that less total energy is used to perform external work of 30 W during wheelchair exercise when using this WCE (VP100 Handisport ergometer). Clinical Trials Protocol Record is NCT00987155/4.2007.2271.

Objective This study aimed to demonstrate that maximal strength training improves muscle strength and to assess the effect of training on function, aerobic status, and quality-of-life among chronic stroke survivors. Design Ten patients acted as their own controls for 4 wks, before an 8-week training intervention. Patients trained 3 days/wk, with four sets of four repetitions at 85%–95% one repetition maximum in unilateral leg press and plantarflexion with an emphasis on maximal mobilization of force in the concentric phase. Results After training, leg press strength improved by 30.6 kg (75%) and 17.8 kg (86%); plantarflexion strength improved by 35.5 kg (89%) and 28.5 kg (223%) for the unaffected and affected limbs, respectively, significantly different from the control period (all P < 0.01). The 6-min walk test improved by 13.9 m (within training period; P = 0.01), and the Timed Up and Go test time improved by 0.6 secs (within training period; P < 0.05). There were no significant changes in walking economy, peak aerobic capacity, Four-Square Step Test, or health-related quality-of-life after training. Conclusions Maximal strength training improved muscle strength in the most affected as well as in the nonaffected leg and improved Timed-Up-And-Go time and 6-min walk distance but did not alter Four-Step Square Test time, aerobic status, or quality-of-life among chronic stroke survivors.

Abstract Objective: To determine the physiological and functional responses from high aerobic intensity treadmill walking in 4 x 4-minute intervals in people with chronic stroke and to evaluate the feasibility of this mode of training. Method: This was a baseline control trial with 1 year follow-up in an outpatient rehabilitation setting at a university hospital. Eight people with chronic stroke participated in and completed the study. Their mean age was 48.9 (± 10.6) years. We tested uphill treadmill walking in 4 x 4-minute work periods at an intensity between 85% and 95% of peak heart rate from initial maximal treadmill testing. There were 3-minute active breaks between the intervals. The main outcome measures were peak oxygen uptake (VO2peak) and walking economy (Cw). Overall compliance and adverse events determine the feasibility. Results: VO2peak increased from 2.32 (± 0.44) to 2.60 (± 0.55) L • min–1 post training (P = .003). Walking economy (Cw) improved from 1.12 (± 0.15) to 1.04 (± 0.18) L • min–1 (P = .043). At 1 year follow-up, VO2peak was 2.59 (±0.58) L • min –1 and was not significantly different from posttraining measurement (P = 1.00). Cw was 1.19 (± 0.15) L • min–1 at 1 year follow-up and thus was worse than post training (P = .023). Functional improvements were found in the 6-minute walk test (6MWT) (P = .020), 10-meter walk test (10MWT) (P = .032), and Timed Up and Go test (TUG) (P = .002) at post tests. Conclusions: High aerobic intensity interval treadmill walking significantly increased VO2peak and improved Cw in these subjects. The training was feasible and may have important implications for cardiovascular health and future rehabilitation programs in this population.

The objective of this study was to compare the neuromuscular function of the paretic and non-paretic plantar flexors (i.e. soleus, gastrocnemius medialis, lateralis) in chronic stroke patients. It was hypothesized that the contractile rate of force development (RFD) and neural activation, assessed by electromyogram (EMG) and V-waves normalized to the M-wave, and voluntary activation (twitch interpolation) would be reduced during plantar flexor maximum voluntary isometric contraction and that the evoked muscle twitch properties would be reduced in the paretic limb. Ten chronic stroke survivors completed the study. The main findings were that the paretic side showed deteriorated function compared to the non-paretic leg in terms of (1) RFD in all analyzed time windows from force onset to 250 ms, although relative RFD (i.e. normalized to maximum voluntary force) was similar; (2) fast neural activation (for most analyzed time windows), assessed by EMG activity in time windows from EMG onset to 250 ms; (3) V-wave responses (except for gastrocnemius medialis); (4) voluntary activation; (5) the evoked peak twitch force, although there was no evidence of intrinsic muscle slowing; (6) EMG activity obtained at maximal voluntary force. In conclusion, this study demonstrates considerable neuromuscular asymmetry of the plantar flexors in chronic stroke survivors. Effective rehabilitation regimes should be investigated.