Five Weeks of Aquatic-Calisthenic High Intensity Interval Training Improves Cardiorespiratory Fitness and Body Composition in Sedentary Young Adults.

Aquatic exercise may be better tolerated by sedentary, overweight individuals than land-based exercise. The purpose of the present study was to determine the effects of five weeks of aquatic high-intensity interval training (AHIIT) using standard calisthenic pool exercises, on cardiorespiratory fitness and body composition in sedentary young adults. Eleven college-age participants (9 women, 2 men) completed 15 exercise sessions that included three sessions per week for five weeks. Each session consisted of a five-minute warm-up period, 25 minutes of exercise, and a five-minute cool down. A training progression based upon standard progression principals from a pilot study was implemented. The exercises consisted of 25 exercise intervals lasting 10-30 seconds in duration, utilizing combinations of 8-12 different exercises. Twenty-two standard aquatic upper body, lower body, and full body aerobic exercises, most of which utilized aquatic dumbbells or hand paddles, were performed in an AHIIT protocol during each exercise session. Reductions in body composition (32.6 to 30.6% fat), submaximal (169 to 165 b·min-1) and peak heart rate (199 to 192 b·min-1), submaximal VO2 (21.7 to 19.3 ml·kg-1·min-1 and peak VO2 (30.5 to 31.95 ml·kg-1·min-1) occurred from pre- to post-program. This is the first study to determine the effectiveness of standard aquatic calisthenic exercises used in an AHIIT protocol. Improvements in cardiorespiratory fitness and exercise economy as well as body composition were observed in these sedentary individuals.

A Hydrothermally Processed Maize Starch and Its Effects on Blood Glucose Levels During High-Intensity Interval Exercise.

Hetrick, MM, Naquin, MR, Gillan, WW, Williams, BM, and Kraemer, RR. A hydrothermally processed maize starch and its effects on blood glucose levels during high-intensity interval exercise. J Strength Cond Res 32(1): 3-12, 2018-A hydrothermally processed maize starch (HPMS) has been shown to blunt initial blood glucose and insulin response during endurance activity at 70% maximal oxygen uptake (V[Combining Dot Above]O2max). High-intensity interval training (HIIT) is a form of exercise that has many health benefits although it is only performed for short periods of time with interspersed rest periods. The purpose of this study was to compare the blood glucose and associated metabolic stress responses to a sprint interval cycling (SIC) exercise protocol (a form of HIIT) with and without an HPMS in a healthy population. Fourteen subjects completed a total of 4 sessions: a preliminary session, an SIC session with HPMS, an SIC session without HPMS, and a control session in which only HPMS was ingested. Blood glucose, blood lactate, respiratory exchange ratio, oxygen consumption, and rating of perceived exertion responses were recorded during the sessions. There was a significant and progressive rise in blood glucose levels during each of the cycle sprints of both exercise sessions, but not a significant difference between treatment or nontreatment SIC sessions. This is the first study to determine blood glucose responses to SIC after each sprint interval and to report that ingestion of HPMS does not affect glucose responses to SIC. The findings provide some preliminary evidence suggesting subjects at risk for glucose excursions could use SIC to improve health through monitoring blood glucose concentrations during SIC and if necessary, modifying number, intensity, and duration of sprints completed.

Validity of Wearable Activity Monitors during Cycling and Resistance Exercise.

INTRODUCTION: The use of wearable activity monitors has seen rapid growth; however, the mode and intensity of exercise could affect the validity of heart rate (HR) and caloric (energy) expenditure (EE) readings. There is a lack of data regarding the validity of wearable activity monitors during graded cycling regimen and a standard resistance exercise. The present study determined the validity of eight monitors for HR compared with an ECG and seven monitors for EE compared with a metabolic analyzer during graded cycling and resistance exercise. METHODS: Fifty subjects (28 women, 22 men) completed separate trials of graded cycling and three sets of four resistance exercises at a 10-repetition-maximum load. Monitors included the following: Apple Watch Series 2, Fitbit Blaze, Fitbit Charge 2, Polar H7, Polar A360, Garmin Vivosmart HR, TomTom Touch, and Bose SoundSport Pulse (BSP) headphones. HR was recorded after each cycling intensity and after each resistance exercise set. EE was recorded after both protocols. Validity was established as having a mean absolute percent error (MAPE) value of ≤10%. RESULTS: The Polar H7 and BSP were valid during both exercise modes (cycling: MAPE = 6.87%, R = 0.79; resistance exercise: MAPE = 6.31%, R = 0.83). During cycling, the Apple Watch Series 2 revealed the greatest HR validity (MAPE = 4.14%, R = 0.80). The BSP revealed the greatest HR accuracy during resistance exercise (MAPE = 6.24%, R = 0.86). Across all devices, as exercise intensity increased, there was greater underestimation of HR. No device was valid for EE during cycling or resistance exercise. CONCLUSIONS: HR from wearable devices differed at different exercise intensities; EE estimates from wearable devices were inaccurate. Wearable devices are not medical devices, and users should be cautious when using these devices for monitoring physiological responses to exercise.