|Who would have thought that barefoot running triggers instant improvements in running economy?|
- The effect of vitamin d supplementation on training adaptation in well trained soccer players (Jastrzebska. 2016) - In view of the fact everybody appears to believe that the currently available evidence would imply that vitamin D supplements could enhance athletic performance, it is hardly surprising that the next issue of the Journal of Strength and Conditioning Research will contain yet another study investigating the effects of vitamin D supplements on athletic performance.
What distinguishes the study at hand from the rest of the pack is that it was conducted in high-level, well trained athletes, who received either a placebo (PG) or 5000IU of vitamin D per day (SG). Both groups were subjected to the same "High Intensity Interval Training Program".
Figure 1: Overview of he training regimen, the subjects were subjected to.
Much to the disappointment of the average vitamin D enthusiast, there were no significant differences between SG and PG groups for any power-related characteristics at baseline. What did work, though, was the training: All power-related variables, except the 30 m sprint running time, improved significantly in response to interval training. However, the mean change scores (the differences between post- and pre-supplementation values) did not differ significantly between SG and PG groups. Thus, the authors of the study conclude that...
Remember the differential effect of Vitamin D on breast cancer risk in lean vs. obese women?
- Acute Citrulline-Malate supplementation and high-intensity cycling performance (Cunniffe. 2016) - Unlike the results of a previously discussed study on the effects of citrulline supplementation during an intense leg workout, in which 8g/day triggered significant performance increases, the recent double-blind, placebo-controlled, crossover study by Cunniffe et al. found no benefits of 12g of citrulline malate (in 400ml) compared to lemon sugar-free cordial (Placebo [PL]) when the 10 subjects consumed it 60 min prior to completion of two exercise trials... or, to be precise, only the heart rate differed significantly.
Figure 2: Mean performance in the two groups; # sign. inter-group difference (p < 0.05 | Cunniffe. 2016)
- Barefoot running reduces the submaximal oxygen cost in female distance runners (Berrones. 2016) - The two most important ways to increase your running performance are (a) improving your VO2max, (b) improving your running economy aka the "O2 costs of running". That this can be achieved as easily as by dropping your shoes is thus a quite important result, Berrones et al. observed in during three 5-minute submaximal running trials representing 65, 75, and 85% of VO2max in fourteen recreationally active, trained distance female runners (age = 27.6 +/- 1.6 yrs; height = 163.3 +/- 1.7 cm; weight = 57.8 +/- 1.9 kg) who were completely inexperienced with unshod running.
Following initial testing, each subject was randomized to either unshod or shod for days 2 and 3. Berrones et al. analyzed the data with a 2-way (condition by intensity) repeated measures ANOVA. The results of this analysis shows that the runners' submaximal oxygen consumption was significantly reduced at 85% of VO2max (P = 0.018), but not during the 65% or 75% trials (P > 0.05, both).
The improvement in VO2 consumption during barefoot running was sign. only for 85% VO2max (Berrones. 2016).
- Berrones, Adam J.; Kurti, Stephanie; Kilsdonk, Korey; Cortez, Delonyx; Melo, Flavia; Whitehurst, Michael. "Barefoot running reduces the submaximal oxygen cost in female distance runners." Journal of Strength & Conditioning Research: Post Acceptance: January 19, 2016. doi: 10.1519/JSC.0000000000001330.
- Cunniffe, Brian; Papageorgiou, Maria; O’Brien, Barbara; Davies, Nathan A; Grimble, George K; Cardinale, Marco. "Acute Citrulline-Malate supplementation and high-intensity cycling performance." Journal of Strength & Conditioning Research: Post Acceptance: January 19, 2016. doi: 10.1519/JSC.0000000000001338.
- Jastrzebska, Maria; Kaczmarczyk, Mariusz; Jastrzebski, Zbigniew. "The effect of vitamin d supplementation on training adaptation in well trained soccer players." Journal of Strength & Conditioning Research: Post Acceptance: January 20, 2016. doi: 10.1519/JSC.0000000000001337
- Wax, Benjamin, et al. "Effects of Supplemental Citrulline Malate Ingestion During Repeated Bouts of Lower-body Exercise in Advanced Weight Lifters." The Journal of Strength & Conditioning Research (2014).