ONLINE DRIVERS MEDIA

Scientific evidence suggests: There is not one optimal protein to build muscle - its the mix of fast to slow proteins thats key.

For someone like yourself, whos making sure to get his daily dose of SuppVersity Science News, the results Reidy et al. present in their latest paper in the Journal of Applied Physiology can hardly be surprising. I have, after all, written about the superiority of whey + casein blends as potential muscle builders only recently ("When Whey & Casein Unite in the Spirit of True Physique Improvements, BCAAs & Glutamine Better Shut the F*** Up"  | (re-)read the article). It was thus only to be expected that a study in which the scientists from the University of Texas Medical Branch compared the effects of the prolonged hyperaminoacidemia thats associated with the ingestion of a blend of plant (25% soy) and dairy (50% casein, 25% whey) proteins (with varying digestion rates) to that of a pure rapidly digested whey would yield a definite points win for the "time-released" formula.
The reasons why its still well worth taking a closer look at the study results are (a) the fact that the f**** up supplement industry is still trying to tell you that protein blends would be inferior to overpriced isolates and (b) the educative value of the post-workout + post-supplementation serum amino acid profiles Reidy et al. observed the 16 healthy, young subjects (age range: 19 –30 yr) who participated in their double-blind, randomized clinical trial (with body fat levels of >24% those were certainly no physical culturists, though ;-)

Figure 1: Graphical overview of the study design (Reidy. 2014)

As you can see in Figure 1 the study protocol involved a standardized resistance training session in the course of which the subjects who had been kept on a diet containing 20% protein, 60% carbohydrate, and 20% fat at 12 kcal/kg for 72h, performed leg extensions on a Cybex-VR2 (Medway, MA), i.e. 8 sets of 10 repetitions at 55% (set 1), 60% (set 2), 65% (set 3), and 70% (sets 4 – 8) of the participants previously determined 1 RM with 3-min rest between sets, before they consumed the protein beverages (Whey or Blend) exactly 1 h postexercise.

Figure 2: Net phenylalanine enrichment (left) and inward and outward transport (right)

The ingestion of the beverages of which the blend and the whey protein contained of 20.1 g total protein (providing 1.9 g leucine, 1.0 g phenylalanine, 1.3 g valine, and 9.0 g EAA; 50% protein from sodium caseinate, 25% protein from whey protein isolate, and 25% protein from soy protein isolate) and 17.3 g of protein (providing 1.9 g leucine, 0.6 g phenylalanine, 1.1 g valine, and 8.7 g EAA; 100% whey protein isolate), respectively, lead to significant increases in amino acid transporter activity (2/SLC38A2, proton-assisted amino acid transporter 1/SLC36A1, cationic amino acid transporter 1/SLC7A1).

"However, the ingestion of the protein blend resulted in a prolonged and positive net phenylalanine balance during postexercise recovery compared with whey protein (P 0.05)." (Reidy)

In view of identical postexercise myofibrillar protein synthesis in both groups this difference may appear negligible. If youve been following my articles about the often oversimplified protein synthesis and increases in skeletal muscle mass, you should be aware that net retention and not fractional synthesis is the term you have to look for, when youre analyzing corresponding studies.
Reference: 

• Reidy, Paul T., et al. "Soy-dairy protein blend and whey protein ingestion after resistance exercise increases amino acid transport and transporter expression in human skeletal muscle." Journal of Applied Physiology 116.11 (2014): 1353-1364.

Isnt HIIT for everyone? Study suggests: Effective- and usefulness of high intensity interval training depend on age and fitness level.

You will remember the two-part article serious about HIIT training "Making HIIT a HIT!" (Part I, Part II) I wrote back in 2012... you didnt well, although I would suggest you read it now, you will understand the idea of personalized HIIT training and there being no single optimal training regimen that works for everyone, anyways - right?

Good! Accordingly, you are not surprised that researchers from tie California State University San Marcos and the Griffith University at the Gold Coast in Queensland, Australia, teamed up to identify individual HIIT-responders and HIIT-non-responders.
The idea was to test whether there would be common denominators in those who do and those who dont respond with improvements in VO2max and lipid oxidation, as well as heart function and heart rate two commonly used modalities of interval training which have been previously-employed in the scientists lab.

"It was hypothesized that frequency of ‘‘non-responders’’ would be less than that typically reported after endurance training" (Astorino. 2014)

The ultimate goal obviously is the development of individualized exercise prescription which may help optimize responses to training and overall health status of various individuals.

In this particular case this meant determining whether the 20 habitually-active men and women who participated in part 1 of the study would show inter-individual as well as inter-group differences compared to the 20 non-obese sedentary women from part 2 of the study.

• In study 1, recreationally-active men and women underwent 2 wk of Wingate-based standardized interval treatment. At baseline and after completion of training, measures of VO2max, HR, and lipid oxidation were determined on separate days at least 24 h apart. Participants were required to maintain their habitual training status which was confirmed with a training log, and time of day was standardized within subjects across all trials. 

• SuppVersity Suggested Read: "More HMB Free Acid Science: Now Its Also Good For High Intensity Interval Training (HIIT) Says the Latest Sponsored Trial W/Out Calcium HMB Control in Young Men & Women" | read more

  In study 2, sedentary young women completed 12 wk of a more tolerable form of interval training at intensities equal to 60–80% or 80–90%Wmax, during which these variables were assessed at baseline and every 3 wk of the study over two separate sessions. They were required to refrain from additional physical activity other than activities of daily living outside of the study. Exercise was performed at approximately the same time of day (#60 min) within participants. In both studies, body composition was assessed pre- and post-training using waist:hip ratio and sum of threeskinfolds (chest, abdomen, thigh for men and triceps, suprailiac, and thigh for women) following standardized procedures.

The fact that we are comparing the short-term effects (4–6 per day at intensities = 200–300%Wmax) over a 2 wk period.) in healthy trained men and women to the long-term effects of 3 d/wk of interval training for 12 wk (six to ten 1 min bouts of cycling at work rates equal to 60–80%Wmax or 80–90%Wmax) in untrained, but still healthy women is allegedly not 100% logical and reduces the significance of the results.

Figure 1: Changes in HR and fat oxidation in trained (left, part 1) & untrained (right, part 2) individuals (Astorino. 2014)

The latter is yet only true for the inter-group, yet not the intra-group comparisons, of which the data in Figure 1 leaves no doubt that it confirms the existance of responsers and non-responders to both regimen:

"Frequency of improved fat oxidation was similar (60–65%) across regimens. Only one participant across both interventions showed nonresponse for all variables." (Astorino. 2014)

Interestingly, the vaseline values of VO2 max, exercise HR, respiratory exchange ratio, and body fat were significant predictors of adaptations to interval training:

• Positive predictors of increases in VO2max were low baseline fitness (difficult to improve whats already top) and high effort during the wingate test.
• Positive predictors of improved heart rate was a high age and a high baseline heart rate
• Positive predictors of increases in fat oxidation were a low baseline physical activity and a low age.

In other words, the short-term wingate protocol (intense HIIT) is most beneficial for the lazy ones, in general and helps the elderly with heart health, and the young with increasing their fat oxidation. For the low intensity chronic regimen things were similar: Body fatness was another non-fitness related positive predictor of increases in VO2max and improvements in heart rate and fat oxidation.
References:

• Astorino TA, Schubert MM (2014) Individual Responses to Completion of Short-Term and Chronic Interval Training: A Retrospective Study. PLoS ONE 9(5): e97638.