eak aerobic exercise capacity, measured as peak oxygen uptake (peak VO 2 ), is a powerful predictor of mortality among cardiac patients. 1 Despite having lower fitness at baseline, women generally do not improve peak VO 2 as much as men in phase 2 cardiac rehabilitation (CR). 2,3 In a prior study of 1789 patients performing standard CR training, women improved by a mean (SD) 0.3 (0.4) L/min and men improved by a mean (SD) 0.4 (0.5) L/min (14% vs 19%, respectively). 3 High-intensity interval training (HIIT) has been shown to be more effective in increasing peak VO 2 compared with moderate intensity continuous training (MCT). However, benefits with HIIT for women are unclear because most studies of HIIT have included primarily men. 4,5 Additionally, resistance training (RT) alone has been shown to improve leg strength and walking endurance in older individuals. 6 The purpose of this study is to examine the combination of HIIT and more intensive RT to maximize peak VO 2 for women in CR. We hypothesized that increases in peak VO 2 (L/min) would be greater among women performing HIIT and additional leg strength training compared with standard MCT. MethodsThis was a randomized clinical study performed from July 2017 to February 2020 and approved by the University of Vermont Institutional Review Board. A detailed protocol is available in Supplement 1. Written informed consent was obtained by all participants.Women entering CR at a community-based cardiac rehabilitation program affiliated with a university hospital in IMPORTANCE Despite lower baseline fitness levels, women in cardiac rehabilitation (CR) do not typically improve peak aerobic exercise capacity (defined as peak oxygen uptake [peak VO 2 ]) compared with men in CR. OBJECTIVE To evaluate the effect of high-intensity interval training (HIIT) and intensive lower extremity resistance training (RT) compared with standard moderate intensity continuous training (MCT) on peak VO 2 among women in CR. DESIGN, SETTING, AND PARTICIPANTS This randomized clinical trial conducted from July 2017 to February 2020 included women from a community-based cardiac rehabilitation program affiliated with a university hospital in Vermont. A total of 56 women (mean [SD] age, 65 [11] years; range 43-98 years) participating in CR enrolled in the study.INTERVENTIONS MCT (70% to 85% of peak heart rate [HR]) with moderate intensive RT or HIIT (90% to 95% of peak HR) along with higher-intensity lower extremity RT 3 times per week over 12 weeks. MAIN OUTCOMES AND MEASURESThe primary outcome was the between-group difference in change in peak VO 2 (L/min) from baseline to 12 weeks. RESULTSPeak VO 2 increased to a greater degree in the HIIT group (+23%) than in the control group (+7%) (mean [SD] increase, 0.3 [0.2] L/min vs 0.1 [0.2] L/min; P = .03). Similarly, the change in leg strength was greater in the HIIT-RT group compared with the control group (mean [SD] increase, 15.3 [0.3] kg vs 6.4 [1.1] kg; P = .004). CONCLUSIONS AND RELEVANCEAn exercise protocol combining HIIT and intensive lower ex...

The influence of weighted heel boots on the duration and start of the stance phases of all four limbs in slow and fast Tolt in the Icelandic HorseThe gait pattern of tolt with weighted heel boots placed on the forelimbs differs from tolt without heel boots. The aim of the study was the documentation of the influence of weighted heel boots on the tolt gait pattern, especially on the pattern of stance phases of all four limbs, with single limb support, two limb support and three limb support phases, both in slow and in fast tolt. Eight sound Icelandic horses (age: 12±3 years, body mass: 369±46 kg) were measured during ridden tolt on the treadmill. Reflecting markers were placed on the skin above the frontal bone, the sacral bone, and all four hooves. Marker movement was traced using a high speed video system (Motion Analysis Corp., 10 cameras, measurement frequency 120 Hz, resolution 1,3 Megapixel). After training on the treadmill without the rider, the two distinct ridden tolt speeds (slow tolt and fast tolt) were identified for each individual horse. Two experienced riders (body mass: 60kg, 62kg) were used to ride 4 horses each. At each speed the movement of the markers was documented in 3 measurement situations: without heel boots, with light-weight heel boots (170g) on both forelimbs, and with heavy heel boots (280g) on both forelimbs. The chronology of the resulting 6 measurement situations was randomized, and in each measurement situation two episodes of 20s were measured. This resulted in a minimum of twenty motion cycles available per situation for further analysis. For further analysis, the motion cycle duration was normalized to 100%, and the stance phases of all four limbs were used to calculate the overlap between the stance phases of all four limbs, the presence of 3 limb support phases. In order to indicate the type of gait diagonal and ipsilateral stance phases were compared, resulting in a value of 0 for clear pace pattern (with only ipsilateral stance phase overlaps), a value of 1 for ideal tolt and a value of 2 for typical trot (with only diagonal stance phase overlaps). Additionally, the angle between the frontal bone marker, the sacral bone marker and the horizontal was calculated, and the range of movement of this angle during motion cycles was used as an indicator of steady head carriage. Normal distribution of values was tested using the Kolmogoroff Smirnoff Test, and subsequent Student's t-tests for paired samples were carried out to test the significance of the differences found. Significance was defined for p values ≤ 0.05. All 8 horses could be ridden on the treadmill and measured in the 6 measurement situations, with an average speed of (2.96±0.30m/s) for slow tolt and (4.10±0.32m/s) for fast tolt. Without heel boots, all horses showed a tolt pattern that was close to pace. As a group, and independent of heel boot placement, the horses showed a significantly higher tolt index in the fast tolt than in the slow tolt (p=0.04). For each of the individual horses, measurement situations could...

The concept of Bare Foot (BF) is based on a naturalistic approach to promote running efficiency through forefoot striking patterns. In Contrast, Lieberman et al, 2010 showed that traditional running shoes with high cushioned heels facilitate a rear foot striking pattern. This pattern of running has been found to be relatively inefficient. Hasegawa et al, 2007, showed that 75% of half marathon runners were rear foot strikers which correlated with slower running speeds, in contrast those athletes who demonstrated mid or forefoot striking patterns were more efficient with faster running speeds. This suggests that a forefoot or mid foot striking pattern may increase performance. To date, the majority of studies investigating the effects BF running have used trained runners with multiple exposures before data collection. This limits the generalizability of the data and may not depict the physiological changes that occur with acute exposure. Purpose: The purpose of this study was to investigate the physiologic response during the acute exposure to BF running. Methods: The subjects consisted of 12 recreational runners with no previous history of BF running. The subjects reported to the lab on two separate occasions for either the shod running trial in which they wore running shoes or the BF trial in which a pair of athletic socks was worn. The protocol for both sessions consisted of a brief warm--up followed by the Astrand Treadmill protocol. VO2peak, local RPE (lower extremity), systemic RPE, and time to exhaustion were collected and analyzed. Results: The results of this study found no statistically significant differences (p>0.05) for time to exhaustion 821.75 ±104.7 and 793.0 ±131.98 seconds, VO2peak 52.05 ± 4.69 and 52.38 ± 7.46 ml/kg/min, local RPE 17.25 ± 2.01 and 17.75 ± 1.86, and systemic RPE 17.17 ±1.59 and 17.42 ±1.00 for shod and BF running respectively. The researchers found that each subject did transition within 60 seconds from rear foot strikers to mid/ fore foot strikers. Conclusion: The findings of this study suggest that there is no difference in physiologic or fatigue values between shod and barefoot running during an acute exposure, however transition of running style did occur. This would suggest that novice runners with no BF experience might in fact benefit just as experienced runners do from BF running.