Intermittent Fasting Diet Plan Example

Caffeine wont do the "last rep" for ya.

Time for a brief review of the latest exercise and supplementation science in the SuppVersity Short News. You can see an overview of all previous articles in an RSS feed here.

This time you can take a look at the surprisingly lasting pro-anabolic effects of HIIT as measured by skeletal muscle protein synthesis in the elderly and the similarly surprising finding that caffeine - even if its consumed in significant doses before a workout - will not have you curl an extra pound on either barbell or dumbbell curls.

• 27% increase in protein synthesis even 24h after HIIT exercise in the elderly - Resistance exercise (RE) and aerobic exercise are recommended for older adults for fitness and strength. High-intensity interval exercise (HIIT) is an understudied but potent potential alternative to aerobic exercise. A recent study from the McMaster University aimed to determine how each mode of exercise affected the integrated day-to-day response of muscle protein synthesis.
  
  To do so, they recruited 22 sedentary men (mean age = 22; 67±4 years; body mass index: 27.0±2.6 kg m- 2 [mean ± SEM]) who were randomly assigned to perform resistance training, aerobic exercise, or HIIT. The participants consumed a stable isotope tracer (D2O) for 9 days. Daily saliva samples were taken to measure tracer incorporation in body water. Muscle biopsies were obtained on Days 5-8 of D2O consumption to measure tracer incorporation into muscle at rest, 24 hours, and 48 hours following each exercise bout: RE (3 × 10 repetitions: leg extensor and press, 95% 10RM), HIIT (10 × 1 minute, 95% maximal heart rate [HRmax]), or aerobic exercise (30 minutes, 55%-60% HRmax).
  

  Figure 1: Myofirillar (left) and sarcoplasmic (right) protein fractional synthesis rate (FSR) at baseline and postexercise. Data are means ± SEM. Bars bearing different letters are signifiantly different within each exercise group | AE = aerobic exercise; HIIT = high-intensity interval exercise; RE = resistance exercise (Bell. 2015).

  What the scientists found is quite surprising: While resistance training showed, as it was expected, the greatest increase in fractional protein synthesis immediately, post workout, only the HIIT protocol lead do significant increases in sarcoplasmic protein fractional synthetic rate 24-hour postexercise (2.30±0.34% d- 1 vs 1.83±0.21% d- 1).
  
  That does not mean that HIIT is the better muscle builder, though. Specifically in view of the fact that its the myofibrilar, not the sarcoplasmic protein synthesis rate that bunks with aging (Balagopal. 1997), the higher myofibrilar post-workout protein synthesis after the relatively low volume resistance training session is more important than the long-lasting elevation of the protein influx into the sarcoplasma, a muscle protein fraction that is involved in the anaerobic ATP production, intracellular transport, and several other enzyme functions. 
• Stronger biceps with caffeine? No, ... at least during insometric contractions the administration of 5 mg/kg and 10 mg/kg caffeine does not have ergogenic effects on the elbow flexors.
  Thats at least what the latest study from the University of Kansas shows. In their 13 recreationally trained male subjects, the ingestion of the aforementioned amounts of caffeine in form of of a caffeineated drink did not lead to significant increases in any of the relevant performance markers.
  

  Figure 2: Caffeine did not have significant ergogenic effects; at least the rate of torque development did increase, though (Trevino. 2015).

  In contrast to previous research which has indicated that under certain conditions, caffeine may increase muscle force production during anaerobic activities (3,6,15,17). The results of our study revealed that caffeine did not significantly affect peak torque during the maximal isometric contractions. As Trevino et al. point out, this finding may result from a variety of factors:

  Figure 3: In contrast to the study at hand a study by Beck et al. found significant increases in bench press performance in slightly better trained subjects (Beck. 2006).

  "Past equivocal findings with caffeine ingestion and anaerobic performance may have resulted from the type of muscle action and exercise performed, caffeine dose used, muscle group tested, or training status of the subjects. Our protocol used a single-joint isometric exercise to test the effects of caffeine doses of 5 and 10 mg/kg of body mass on maximal strength of the elbow flexors in resistance trained males (participating in at least 2 training sessions per week). Beck et al. (2006) reported that a 201 mg dose of caffeine significantly increased bench press 1RM in resistance trained males (participating in at least 4 training sessions/week). 

  Because significant results were found with a caffeine dose less than ours (average absolute doses in the current study were 426.7 and 853.4 mg for the 0 and 5 mg/ kg body mass conditions, respectively), it seems that the exercise test and training status may have led to different findings between the studies" (Trevino. 2015).

  Next to the training status and the lack of familiarity with performing maximal muscle contrations (the subjects in Beck et al. (2006) trained 4 times per week, the ones in the study at hand only two times), the exercise may play a role as well. The bench press is after all a multi-joint exercise requiring dynamic involvement of the pectoralis major, deltoid, and triceps. The biceps curl, on the other hand is the classic single-joint exercise, where the CNS activating effect of caffeine may simply offer less benefits than on bench presses, squats and other multi-joint exercises. The same may be true for comparisons of large and small muscle groups and could explain why Astorino et al. (2010), Jacobson, et al. (1992) and Kalmar et al. (1999) found beneficial effect of caffeine on the leg extension performance of their subjects, while Trevino et al. were not able to detect ergogenic effects for the small elbow flexors.

References

• Astorino, Todd A., et al. "Effect of two doses of caffeine on muscular function during isokinetic exercise." Medicine and science in sports and exercise 42.12 (2010): 2205-2210.
• Balagopal, P., et al. "Effects of aging on in vivo synthesis of skeletal muscle myosin heavy-chain and sarcoplasmic protein in humans." American Journal of Physiology-Endocrinology And Metabolism 273.4 (1997): E790-E800.
• Beck, Travis W., et al. "The acute effects of a caffeine-containing supplement on strength, muscular endurance, and anaerobic capabilities." The Journal of Strength & Conditioning Research 20.3 (2006): 506-510.
• Bell et al. "Day-to-Day Changes in Muscle Protein Synthesis in Recovery From Resistance, Aerobic, and High-Intensity Interval Exercise in Older Men." J Gerontol A Biol Sci Med Sci (2015). 
• Jacobson, B. H., et al. "Effect of caffeine on maximal strength and power in élite male athletes." British journal of sports medicine 26.4 (1992): 276-280.
• Kalmar, J. M., and E. Cafarelli. "Effects of caffeine on neuromuscular function." Journal of Applied Physiology 87.2 (1999): 801-808.
• Trevino, Michael A., et al. "Acute Effects of Caffeine on Strength and Muscle Activation of the Elbow Flexors." The Journal of Strength & Conditioning Research 29.2 (2015): 513-520.

Alanine is the livers favorite gluconeogenic amino acid and leucine appears to increase its usage.

Being among the first to learn about the "Glucose-Repartitioning Effect of Iso-Leucine" in February 2013 (read up on it), you, as SuppVersity reader, belong to the selected few who know that valine and isoleucine may be more than unnecessary props in the leucine-powered BCAA show. With the recent publication of a rodent study from the University of Sao Paulo in Brazil (Campos-Ferraz. 2013), however, it looks as if you had to revise your perspective on the purportedly auxiliary BCAAs - at least, with respect to their ability to reduce fatigue, and muscle and liver-glycogen degradation, in trained rats and possibly (!) humans.

So what did the Brazilian researchers do?

Basically, the idea Campos-Ferraz et al. had in mind, when they came up with their 8 week exercise + 2 week supplementation protocol (see Table 1) was to ...

Table 1: Exercise progression; suppl. was initiated in w7 after lactate test

"evaluate effects of the use of supplementation with leucine or a mixture of BCAAs in trained rats submitted to an exercise-induced protocol of glycogen depletion.

Furthermore, we attempted to investigate muscle and liver biochemical parameters that were not performed in the previous study in order to elucidate the role of BCAAs in glycogen depletion. " (Campos-Ferraz. 2013)

In other words: The researchers wanted to find out whether or not leucine would exert identical, less or more pronounced effects on muscle glycogen use and endurance performance in rodents that the full spectrum of branch-chained amino acids, i.e. leucine, valine and isoleucine.

Contrary to what bro-science and the shiny ads of the supplement industry are suggesting, the scientists fundamental hypothesis was that the BCAAs supplementation would impair the rodents endurance capacity, because the branched-chain amino acids would be used in muscle to yield acetyl-CoA. This, in turn could reduce the activity of the glucose-alanine cycle, by which the muscles are supplied with alanine-derived glucose from the liver and (once the BCAAs got burne) result in an earlier onset of fatigue.

BCAAs are "glycogen depleters"?!

If you take a look at the data Campos Ferraz et al. gathered in the testing sessions at the end of the supplementation period, in the course of which the rats received an oral gavage of 166mg/kg per day (in human terms this would be ca. 3-3.5g per day) of BCAAs or leucine, it is quite obvious that the  the leucine group had a significantly lower muscle and liver glycogen degradation ratios than the BCAA group.

Figure 1: Liver & mucle glycogen degradation and time to exhaustion (expressed relative to placebo); muscle TCA intermediate content and enzyme activity / concentration (Campos-Ferraz. 2013)

Compared to the placebo group, only the ratios were different.  While the placebo group had the lowest liver glycogen use and a high muscle glycogen use, the supplemental leucine induced a shifted from muscle to liver glycogen and did thus exert muscle specific glycogen sparing effects.

As the researchers point out, these observations stand in line with their original hypothesis: Leucine can spare a significant amount of muscle and liver glycogen and thus produce a highly significant increase in resistance to exhaustion compared to the mixture of BCAAs (P<0.001).
If we compare the endurance performance of the leucine rodents to that of the placebo group, this does yet cast a slight shadow on the overall image of the glorious ergogenic, and, even more so, the purported performance enhancing effects of BCAAs. Despite measurable differences in the time to exhaustion, the actual endurance increase in response to the leucine supplement is relatively small.
 
If you take another look at the data in Figure 1 you will probably notice the significant increase in TCA cycle intermediates (citrate and malate) in the BCAA group. These changes provide further evidence that the provision of all three branch-chain amino acid emphasized the use of glucose as a main substrate to sustain the endurance activity.

"Mouse vs. man": Can we ignore the differences in BCAA metabolism?


At this point, it may however be about time to point out that the activity of the BCAA catabolizing enzyme branched-chain keto acids dehydrogenase complex (BCKD) in humans is quite different from that in rats.

"In the latter [the rat], liver BCKD is almost completely unphosphorylated (activated) in basal state, making it possible to metabolize more rapidly BCKA from the portal blood; in humans, BCKD in liver is normally phosphorylated (inactivated) in order to spare BCAAs for protein synthesis." (Campos-Ferraz. 2013)

In other words: While rodents use BCAAs mostly as an energy source, the human body spares them as a potential protein anabolic.

In view of the fact that the BCAAs are not used to the same degree as an alternative substrate in the human vs. the rodent liver, it is actually not very surprising that the results of the study at hand appear to conflict with data from a previous study by the same laboratory (Gualano. 2011). In the corresponding experiment, Gualano et al observed measurable increases in exercise capacity and lipid oxidation in human subjects during endurance exercise after muscle glycogen depletion in response to the provision of 300mg/kg BCAAs per day.

Reference:

• Campos-Ferraz PL, Bozza T, Nicastro H, Lancha AH Jr. Distinct effects of leucine or a mixture of the branched-chain amino acids (leucine, isoleucine, and valine) supplementation on resistance to fatigue, and muscle and liver-glycogen degradation, in trained rats. Nutrition. 2013 Nov-Dec;29(11-12):1388-94.
• Gualano AB, Bozza T, Lopes De Campos P, Roschel H, Dos Santos Costa A, Luiz Marquezi M, et al. Branched-chain amino acids supplementation enhances exercise capacity and lipid oxidation during endurance exercise after muscle glycogen depletion. J Sports Med Phys Fitness 2011;51:82–8