23 Apr 2017
By Laurie Edge-Hughes, BScPT, MAnimSt (Animal Physio), CAFCI, CCRT
A very interesting blog crossed my desk.
Basically, the article discussed how often you should train a muscle group (i.e. the Glutes) in order to grow it as fast as possible! Fun, right? It talked about the concept of muscle SRA. SRA stands for Stimulus, Recovery, and Adaptation. We know that muscle protein synthesis increases during Recovery and Adaptation and can stay elevated for up to 4 days. It is the type of exercise that determines how long the muscle needs to go through the SRA process (and hence when to work out the muscle again.) Here’s a clip from the article:
“The S in muscle SRA is for Stimulus. During a training session, you break down the muscle, the Stimulus for growth. Because of this, the muscle’s functional size – the part of the muscle that’s still able to contract – decreases. The body will then rebuild the broken-down muscle. This is called Recovery, the R in SRA. After the body is done rebuilding, it prevents future breakdown of the muscle from happening. It does this by building the muscle bigger than before. This is called Adaptation, the A in SRA. The muscle is now more resistant to a future Stimulus. However, if this Stimulus is too much, it can cause trouble in the recovery/adaptation process.”
If you break down an exercise into the factors that impact the recovery / adaptation time, you must pay attention to: 1) muscle activity, 2) range of motion, 3) emphasis on eccentrics, and 4) muscle length at peak tension. Here’s how that information ties in:
“1. Muscle activity - Low muscle activation equals low muscle tension, which leads to a small stimulus that has a short recovery time. High muscle activation equals high muscle tension, which leads to a bigger stimulus that has a longer recovery and adaptation time.
2. Range of motion - When an exercise brings a muscle through a bigger Range of Motion (ROM), the muscle does more work (muscular work = muscle force/tension x excursion/distance).
3. Emphasis on eccentrics - Early research shows that heavy eccentrics break down the muscle more than heavy concentric movements.
4. Muscle length at peak tension - More recent studies also show that firing muscles hard when they’re lengthened causes more muscle breakdown compared to when they’re shortened. As expected, these exercises also took longer to recover and adapt from.”
Ideally, in order to grow a muscle, you need to train a muscle as soon as recovery and adaptation of the muscle is completed. The article discussed glute exercise types, and categorized them as ‘Stretchers, Activators, and Pumpers’. Full squats combine ROM and eccentrics, making them a Stretcher exercise. These would take a longer time to recover from. Barbell Hip Thrusts use less ROM but if done correctly (i.e. slowly lowering), can require more eccentric control, making this more of an Activator exercise. This might take 2 to 3 days to recover after this exercise. Lastly, Band Side Walks uses very small ROM and low average Glute activity, and peak activity in a shortened position. Thus, this exercise is a Pumper exercise. Recovery from this type of exercise would be the shortest (i.e. It could be done daily!)
The paper commented that different people respond better to different kinds of exercise types. So, you may need to do some trial and error. Additionally, the body is an adaptive system, so you may need to change up the exercise type in order to make a new gain in muscle growth and strength.
While this is all great information… and we should be expecting each other to have firm high glutes the next time we meet, what does this mean for our canine companions? Well, the same principles would apply.
So, let’s pick some exercises / exercise types and think about the Glutes as well:
- Walking or trotting in the UWT – there’s no extremes in ROM, there’s minimal to no eccentric components, peak tension would be mid-range, and muscle activation is low. In MY opinion it’s a Pumper exercise. It could be done frequently – as it relates to MUSCLE GROWTH. (It has cardiovascular effects, which need to be taken into consideration, but for this article, we’re talking muscle growth).
- Hill walking – (lets’ think glutes for this as well) Going uphill would require greater ROM, a peak activation in a lengthened state, and high muscle activation. I’m thinking this is a Stretcher-type exercise. A dog would need more rest between exercise session using hill climbing activities.
- Sit to stands facing up hill – Now we have eccentric control, peak activation in a lengthened position, full ROM, and high muscle activation. Oooh, this one is a Stretcher as well. More rest required after a workout before doing this exercise again.
- Squat blocks (Members, check out Training Video 7 – Fun with Cinderblocks) – Here we have high muscle activation, a little bit of eccentric use, peak activation is not quite at the most lengthened position and ROM is moderate. Let’s give this one an Activator designation.
Now, since our dogs can’t tell us how sore their glutes are after exercise, we’re likely going to have to make some assumptions, and watch them for signs of soreness and discomfort. And don’t forget that ‘rest’ can be active rest (i.e. walks, exercising different muscle groups, or lower intensity Pumper exercises). So, put these concepts into your thought-processing when you are doing your exercise prescription. Perhaps give different exercises to do on even versus odd days, and/or provide owners with information about resting between training sessions.
Now, as a caveat, I think it needs to be said that REHAB exercise prescription is often different than CONDITIONING exercise prescription. We don’t often push our REHAB patients to the point of muscle fatigue (especially not in the early stages), but for a fit, activity, healthy sporting dog, we certainly should think about these concepts. It also brings forth the need to test an exercise before prescribing it, to watch the dog and see just how difficult the exercise is for him / her. It’s fun to get to work with these principles and I just think it’s interesting to think about too!
16 Apr 2017
By Laurie Edge-Hughes, BScPT, MAnimSt(Animal Physio), CAFCI CCRT
We’ve all heard the lactic acid lies! Chances are good you may have even repeated them even! What we believed lactic acid was and did isn’t at all true. In the mid 2000’s Lactic Acid was the ‘bad guy’. By 2010, we knew it wasn’t Lactic Acid, but instead Lactate. And by 2015, we were grasping the concept that it’s a good thing and a fuel source. If you’re not yet up to speed on the Lactic Acid Lies, better keep reading!
The List of Lies:
1. Muscle don’t produce lactic acid, they produce lactate. (“PoTAYto”, “PoTATTo”, right?) Lactate is an intermediate link between anaerobic an aerobic metabolism… not a waste metabolite
2.Lactate does not cause muscle fatigue by making muscle too acidic to contract. Conversely, it actually helps reduce fatigue by mitigating the effects of ‘depolarization’. Depolarization occurs with intense exercise.
3.Lactate does not cause post-exercise muscle soreness. Post-exercise muscle soreness is actually caused by simple mechanical damage to muscle fibers, free radical damage, and inflammation.
4.Exercise performance is not impeded by lactate. In fact, lactate production can stimulate the biogenesis of mitochondria in the muscles, and mitochondria are the little factories that produce energy (remember the Krebs cycle?).
5.Lactate is not a waste product. 75% of the lactate produced in muscles cells is metabolized aerobically and used directly as fuel for muscle contractions, and 25% is recycled into the bloodstream and converted to glucose that can be utilized by the brain, heart, and muscles.
6.Better athletes do no produce less lactate. That simply doesn’t make sense in light of what we’ve already learned. Yes, there is less measureable lactate in the blood stream in elite athletes, but it is more likely that those athletes use 85% for muscle contractions and only release 15% to the blood stream!
Endurance training in particular stimulates the adaptation to use more lactate during activities, and to use it more efficiently. In trained subjects, lactate is actually a preferred energy substrate over glucose… which is great, because when you use up your glucose stores, they’re much harder to replenish!
Last year I attended the Orthopaedic Division Symposium (at the Canadian Physiotherapy Association’s Congress), and was blessed to listen to Delia Roberts, PhD, FACSM speak on ‘Metabolic Considerations for Training Program Design’. She was a great speaker, and very knowledgeable! One thing she had stated, as it pertains to Lactate, is that whenever she is reviewing or looking at a new textbook on exercise physiology, she discards or discredits the book if they have a chapter devoted to “Lactic Acid”. She too reiterated that lactate is not bad and is a fuel source. We should be ‘talking smack’ about hydrogen instead. Hydrogen causes acidosis.
Okay… so now you know, you can ease up on poor old Lactate. It’s been trying to help you out for years, but only just recently is getting the credit it deserves. What is really causing your muscle soreness? Well that’s a blog for another day!
3.Delia Roberts: Metabolic Considerations for Training Program Design. Presentation at the Ortho Division Symposium, May 26 2016, Victoria, British Columbia, Canada.