What happens to protein synthesis & degradation rates and amino acid accumulation within muscle fibres in the hours after heavy resistance training? What influence does your pre- or post-exercise food intake have on these responses?
In the hours after heavy resistance training (HRE), Fractional synthesis rates (FSR) and fractional breakdown rates (FBR) both increase. However, providing essential amino acids (EAA) are available, FSR will generally exceed the FBR.With an increase in blood flow, post HRE, EAA levels increase in availability and are shuttled to the free amino acid pool to be used as a fuel source for both anabolic and catabolic processes. This increase in concentration can promote protein synthesis and buffer against a catabolic hormones (e.g. cortisol) seeking to cause catabolism such as neoglucogenesis through protein muscle breakdown. In order for the RT to result in hypertrophy, the following conditions require an optimal environment during the period of FSR of 36-48 hrs to exceed the FBR of 24-36 hrs. Muscle synthesis is synergistic with nutrition and food timing. The post-absorptive phase occurs ~3 hrs after eating, and although FSR still occurs in a fasted state, protein (inc. aminos) and adequate diet is required for a substantial NET hypertrophic gain.Eating before a workout (e.g. BCAA's & high GI carbohydrates) may ensure the building blocks for FSR are available and based on corresponding endocrinological processes will hopefully reduce catabolism and presence of stress hormones such as cortisol. Sugars from carbohydrates are also used in conjunction with insulin elevation which stimulates and is regulated by mTOR growth pathways, increasing chances of protein synthesis.
What are the typical acute metabolic responses of muscles involved in resistance training?
Acute responses to post HRE fatigue:1. small decrease in ATP (e.g. 21%)2. large decrease in CrP (e.g. 49%)3. significant increase in Creatine production (100%)4. moderate decrease in Glycogen (28%)5. massive increase in Lactate (1000%)- Improvements in ATP-PcR systems- Improvements in Lactate production (higher lactate threshold)- Improved Anaerobic Capacity - Improved mitochondrial density - Glycogen super-compensation- hypertrophy - muscle Oedema
Describe the changes in concentration of the major anabolic hormones during heavy resistance training
FOCUS: Plasma shift is the main cause:- Extent of the plasma shift (into active muscles) will vary with muscle mass involved, duration of sets, rest period between sets and intensity of RT. - GH concentration is thought to be stimulated by blood lactate and lactate production Other Factors:1. Endocrine glands may increase output, and therefore concentration2. removal of hormone from the blood may decrease because blood is directed away from the liver, increasing homeostatic concentrationsIn the Blood:Testosterone: increasesInsuline: stays the same or decreases IGF-1: increases *However, little evidence they enter the muscle and contribute to hypertrophyIn the Muscle: IGF-1: IncreasesMechano Growth Factory (MGF): Increases*Both may have an important role in muscle growthBlood lactate and holding your breath also increases growth factor concentrations
Describe the typical cardiovascular responses to a set of heavy leg presses
45 degree leg press significantly increases BP because your head is relatively low compared to the legs. Affected by posture: BP response somewhat less in seated upright leg press.BP undershoot post exercise- BP lasts seconds (Arterial pressure may go from 250 to 70). Not a great time to jump up out of the machine.
What are the factors that influence the extent of blood pressure elevation during resistance training?
1. Load lifted (for 1 rep)2. Number of reps in the set3. Intensity of effort (how close to failure is the set taken?): The closer to failure, the higher the BP- Also, Neural Drive 4. Exercise selection (Muscle mass involved): The larger the muscle mass, the higher the BP response5. Contraction Mode: Eccentric smaller than concentric
How might you perform RT exercises so as to minimise BP elevation while maintaining a high training intensity and maximal intensities of effort?
1. Favour unilateral over bilateral exercises2. Keep reps low (1-5 with 1-5 RM loads!)3. Pause every 1-3 reps during the set (Baum et al 2003)4. Stop 1-3 reps short of failure (Will reduce gains in strength but not power)(Last resort)5. Use eccentrically-biased methods (2 increased, 1 decreased methods with machines, e.g. leg press - this means to lift with 2x legs, lower with 1)(Sets of 8-10 @ 50% of bilateral 1RM)
What is wrong with the common view that BP responses are lower when we perform higher repetition sets (10-15) with lighter loads?
Lighter loads, with high reps actually results in a higher blood pressure response due to the large quantity of concentric movements.Concentric contractions have been shown to increase in peak pressure with each rep, where more effort is required. This is particularly relevant during Bilateral exercises where more muscle mass must be contracted in order to perform the exercise.
Why is it advisable to stay seated for 3-5 seconds and stand-up slowly after a heavy set of leg presses?
BP undershoot in pressure post exercise- BP lasts seconds (Arterial pressure may go from 250 to 70). This may cause faintness. Not a great time to jump up out of the machine.
A question from left field. A potential client approaches you for exercise advice. He is an actor who has to play a character with a little more muscle mass than he currently has. The problem is that it is just a few weeks until the play and you are aware the muscle hypertrophy is minimal in this time period. From what you have learned in this lecture, what advice can you give him?
It is possible to increase his muscle mass temporarily (for ~45 minutes), by up to 10% using the swelling caused by muscle Oedema. If he continues his HRE pre-shoot, but also perfects maximising the benefit of increased plasma concentrations by using techniques such as high reps (10-15) and low rest (0.5-2), he is more likely to appear like he has more muscle mass.