|Does the kcal-counter on your elliptical lie to you? Does HIIT boost HDL? Find the answers to these and other questions in this installment of the short news.|
All of the studies were conducted as part of masters thesis and/or PhD thesis and none of them has yet been published as full-text. Practically speaking, this means that I can't give you all the intricate details, because I have to rely on the summary of the results in the corresponding abstracts.
- Leg Lean Mass Adaptations Following Short-Term Barbell Training in Women - Since the adaptations associated with classic, barbell-based resistance training in women are not as well understood as those for men, Mota et al. (2015) examined the effects of a four week resistance training intervention on changes in leg lean mass in untrained, college-aged women.
Thirty-five women (mean ± SD age = 21 ± 3 years; body mass = 61.9 ± 10.4 kg) with no previous lower body strength training experience were randomly assigned to high volume training (n = 11), low volume training (n = 10), and control (n = 14) groups. The training groups performed the barbell back squat and deadlift twice per week for four weeks. The low volume training group performed five repetitions of two sets per exercise; the high volume group performed an additional two sets per exercise.
Figure 1: Summary of the main results of the study (Mota. 2015).
The results indicated that there was a statistically significant difference among the adjusted post-test means. Specifically, when the pre-test scores served as the covariate, the mean leg lean mass for the high volume training group was 0.503 kg greater than that for the control group (p = 0.031, 95% CI for adjusted mean difference = 0.038 to 0.968 kg). The pre-test – post test effect sizes for the high volume training and low volume training groups were 0.31 and 0.29, respectively.
- High-Density Lipoprotein Antioxidant Responses to High-Intensity Interval and Steady-State Moderate-Intensity Exercise - High-intensity interval exercise (HIIE | also HIIT) may impart health benefits beyond what is acquired through moderate-intensity steady state exercise (SSE).
From previous studies we know that Paraoxonase 1 (PON1), an antioxidant associated with high density lipoprotein (HDL), may be altered with exercise; however, it is unclear whether HIIE provides a greater stimulus for increasing PON1 antioxidant activity than a comparable or greater amount of SSE. The purpose of the latest study by Papadakis et al. was thus to
"determine the influence of HIIE on PON1 concentration and activity relative to a comparable amount of moderate-intensity SSE and a dose that is half that of SSE" (Papadakis. 2015).To this ends 17 male participants (age 27.8 + 6.4 yr; weight 80.6 + 9.0 kg; BMI 25.1 + 2.4 kg/m2; %fat = 19 + 5; VO2max 52.1 + 7.5 ml/kg/min) underwent HIIE by treadmill running (90% and 40% of VO2reserve in 3:2 min ratio) to expend 500 kcals (H500); HIIE to expend 250 kcals (H250), and; SSE at 70% VO2reserve to expend 500 kcals (M500) in a randomized crossover design.
The intensities of all exercise conditions averaged 70% VO2reserve. Blood measures of total antioxidant capacity (TAC) in copper reducing equivalents, HDL ( g/mL), apolipoprotein A-1 (ApoA1: g/L), PON1 concentration (PON1c: g/mL) and arylesterase activity (PON1a: kU/L) were obtained just before, immediately after, 2 hr and 24 hr after exercise.
Figure 2: Overview of the most significant results (Papadakis. 2015).
Thus, the study clearly proves that HDL and HDL antioxidant properties are transiently potentiated by HIIE - and that with as little as 250 kcals of energy expenditure. Moreover, HDL antioxidant activity and total antioxidant capacity are elevated with HIIE and SSE of moderate intensity in a similar manner and are observed for up to 24 hr after exercise.
Twenty one volunteers completed a bout of body squats to exhaustion holding a 3.63 kg (8 lb.) weight for men and a 2.27 kg (5 lb.) for women, and after a one-minute rest did the same again but without the weight. This was immediately followed by a 20-minute Swedish massage on either the right or left leg (randomized), specifically the hamstrings, quadriceps, and gluteal muscles.
After the massage was performed participants were then asked to report the soreness of treated leg after 24- and 48-hrs using a standard 0-10 pain scale. The results showed:
- A 2 (leg) X 2 (time) factorial ANOVA with repeated measures on the second factor indicated perceived soreness in the treated leg was significantly reduced compared to the untreated leg at 24 hrs (p = .003) and 48 hrs (p = .017).
- While soreness was significantly higher after 48 hrs compared to 24 hrs in the untreated leg (p = .012), soreness in the treated leg was also significantly higher between the same time points (p = .007), but to a lower magnitude.
- Do Elliptical Trainers Accurately Estimate Energy Expenditure? According to a recent study by Vallecillos et al. (2015), the answer to this question depends on the brand you are using. The researchers tested the accuracy of Life Fitness (95X) and Precor (EFX 556i) elliptical exercise trainers which are very popular in fitness centers.
Three men and three women performed exercise sessions on each elliptical trainer on 3 separate occasions (2 bouts per day). The order of the machines used for each exercise session was randomized. Each exercise bout lasted 12 minutes (2-min warmup at a resistance of 3, rpm of 70; 10-min measure period at a resistance of 10, rpm of 70). During the test VO2 was measured using a Medical Graphics Ultima metabolic cart; heart rate was measured using a Polar heart rate monitor and energy expenditure calculated by the metabolic cart. HR, VO2, and energy expenditure data were recorded each minute of the 10 minute exercise session.
Figure 3: Comparison of the kcal calculations of the elliptical and the calculations the scientists made based on combined heart rate & metabolic data (Vallecillos. 2015)
- Bentley, Carol A., et al. "The Effects of Shoe Design on Lower Limb Running Kinematics." International Journal of Exercise Science: Conference Proceedings. Vol. 2. No. 7. 2015.
- Mota, Jacob A., et al. "Leg Lean Mass Adaptations Following Short-Term Barbell Training in Women." International Journal of Exercise Science: Conference Proceedings. Vol. 2. No. 7. 2015.
- Papadakis, Zacharias, et al. "High-Density Lipoprotein Antioxidant Responses to High-Intensity Interval and Steady-State Moderate-Intensity Exercise." International Journal of Exercise Science: Conference Proceedings. Vol. 2. No. 7. 2015.
- Smtih, John D. "DOMS After Acute Strenuous Exercise and Massage." International Journal of Exercise Science: Conference Proceedings. Vol. 2. No. 7. 2015.
- Thompson, Erin F., et al. "Establishing the Learned Effect of Repeated Wingate Anaerobic Tests." International Journal of Exercise Science: Conference Proceedings. Vol. 2. No. 7. 2015.
- Vallecillos, Kevin, et al. "Do Elliptical Trainers Accurately Estimate Energy Expenditure?." International Journal of Exercise Science: Conference Proceedings. Vol. 2. No. 7. 2015.