Each +30 Min/d of Physical Activity Reduce HbA1c by 11%, Protein + CHO Maintain Bone Mass, Overlooked Benefits of BFR, New Marker of Overtraining - Jan '17 Science Update
| This is what the Jan '17 Science Update has to offer? -11% HbA1c reduction per 30 minutes activity, new benefits of blood flow restricted tr., the bone protective effect of immediate post-workout whey plus carb ingestion, and a new overtraining gauge...|
- Scientists find new marker of overreaching and potentially -training: You know that exercise will increase the levels of the allegedly "bad" cytokine IL-6. Now, as a SuppVersity reader, you will yet also know that this "cytokine" is, in fact, a "myokine" if it is released in response to muscle contractions and that it appears to figure in the hormetic response to exercise stress... or, in other words, without it, you're not going to get the adaptational response in form of strength and size gains you're training for. With that being said, studies also show that significantly elevated levels of IL-6 can also occur with overtraining and are - in this situation - a sign of dysfunctional adaptation.
Recent research does now suggest that the "dichotomous nature of IL-6 signalling appears to be determined by the respective concentration of its receptors (both membrane-bound (IL-6R) and soluble (sIL-6R) forms)" (Cullen. 2017) - measuring these concentrations could thus provide important information about whether the circulating IL-6 is going to trigger a hormetic response or not. Accordingly, Cullen et al. conducted a study that investigated the response of sIL-6R to long-term training, and the relationship between sIL-6R, self-reported measures of wellbeing, and upper respiratory illness symptoms (URS) in highly-trained endurance athletes.
This is obviously not enough to use sIL-6R as an overtraining gauge. With future studies that determine the level of sIL-6R in overreaching and overtraining athletes, it may thus be possible to distinguish between these states (and regular training) and to use this information to optimize athletes and gymrats workout routines.
- Rapid Force Capacity (RFC) increases sign. with blood flow restriction, but study shows: Adaptation takes time: This observation Nielsen, et al. (2017) made in their recent study is an important one, because it implies that previous studies on the effects of blood flow restriction + low-intensity training may simply have missed the beneficial effects when they measured (just as Nielsen, et al. did it, too), the adaptational response only 5 days after having subjects participate in a series of standardized workouts.
In the study at hand, this series constituted of twenty-three training sessions which were performed within 19 days. In all 10 male subjects (22.8+/-2.3 years) who performed four sets of knee extensor exercise (20%1RM) to concentric failure during concurrent BFR of the thigh (100mmHg), and the eight work-matched controls (21.9+/-3.0 years) who trained without BFR (CON), the scientists tested the maximal slow and fast knee joint velocity muscle strength and rapid force capacity (e.g. RTD) as well as evoked twitch contractile parameters before and after the study.
Figure 2: Changes in rate of force development (left) and mean muscle fibre area (right | Nielsen. 2017).
- Each extra 30 minutes of daily moderate to vigorous physical activity improve HbA1c of subjects at increased T2DM risk by 11%: MVPA aka "moderate to vigorous physical activity" is the buzzword of the fitness tracker generation. Now, a three-year study confirms what the medals your fitness tracker software will award to you already suggested: each minute spend moving at moderate to vigorous intensity is an investment into your health and well-being.
How Accurate Are Activity Trackers? EE Data From Omron, Fitbit, Jawbone & Other Devices Reveals 10% Error & More | read the full SV article
- Immediate Protein + CHO post-workout nutrition protect your bone from the bone resorption in the hours after exhaustive running: Next to its important result, there are two things which make a recent study by Rebecca Townsend et al. particularly interesting. Firstly: The subjects were young, healthy men, not post-menopausal women as in so many other bone health studies; and second- and not less importantly, the study tested both the efficacy of a mix of 1.5g/kg dextrose + 0.5g/kg whey as a means to reduce bone resorption (=calcium leeching) markers and the effects of timing.
In this context, however, it is important to realize that that, eventually, i.e. 3-4h after the run, the level of β-CTX decreased to similar below pre-test levels in all groups. Practically speaking this means that the net effect of a single session of exhaustive exercise on the young men's bone was almost certainly positive, irrespective of whether and when they ingested the supplement.
- Cullen, Tom; Thomas, Andrew W.; Webb, Richard; Phillips, Thom; Hughes, Michael G. "sIL-6R Is Related to Weekly Training Mileage and Psychological Well-being in Athletes." Medicine & Science in Sports & Exercise: Post Acceptance: January 24, 2017.
- McCarthy, Matthew; Edwardson, Charlotte L; Davies, Melanie J; Henson, Joseph; Gray, Laura; Khunti, Kamlesh; Yates, Thomas. "Change in Sedentary Time, Physical Activity, Bodyweight, and Hba1c in High-Risk Adults." Medicine & Science in Sports & Exercise: Post Acceptance: January 24, 2017.
- Nielsen, Jakob Lindberg; Frandsen, Ulrik; Prokhorova, Tatyana; Bech, Rune Dueholm; Nygaard, Tobias; Suetta, Charlotte; Aagaard, Per. "Delayed Effect of Blood-Flow-Restricted Resistance Training on Rapid Force Capacity." Medicine & Science in Sports & Exercise: Post Acceptance: January 23, 2017.
- Townsend, Rebecca; Elliott-Sale, Kirsty J.; Currell, Kevin; Tang, Jonathan; Fraser, William D.; Sale, Craig. "The Effect of Postexercise Carbohydrate and Protein Ingestion on Bone Metabolism." Medicine & Science in Sports & Exercise: Post Acceptance: January 24, 2017.