This is an excerpt from Anatomy of Speed, The by Bill Parisi.
The first thing to note is that when we talk about performance recovery (as opposed to injury recovery), most people tend to think about what can be done to accelerate healing, reduce pain, and rebuild tissues between bouts of training and competition. While adequate recovery between bouts is important to improving speed and injury resilience, what often gets overlooked is the importance of including recovery protocols within workout bouts—between reps and sets.
“Traditionally, with speed or power training, athletes will repeat a series of high-intensity sprints or lifts or whatever without thinking much about the need for recovery between those reps,” says Michol Dalcourt, founder of the Institute of Motion. “But the question we need to ask is: Why are we doing these reps? If we’re doing these reps for generalized conditioning, well, that’s fine. But if we’re working on developing speed and power, then the intention needs to be high, which means we’re revving the engine high. And when we rev the engine like that over a series of efforts, we are depleting the body’s systems. So those high-intensity efforts need to be balanced with recovery measures that help you reconstitute those systems during the training bout so you can continue to perform at a high level.”
When it comes to in-bout recovery, there are three key strategies that need to be addressed: metabolic recovery, neural recovery, and fluid recovery. Understanding how the body’s systems are depleted during high-intensity efforts and what can be done to restore them during a training session is essential for improving long-term performance and reducing injury risk.
As mentioned in chapter 2, the body generates the metabolic fuel required for muscle contractions (ATP) using three different energy systems: the ATP-PC system, the lactic acid system, and the aerobic system. The ATP-PC system provides the most immediate energy source because it is fueled by phosphocreatine (PC), which is a high-energy chemical compound stored directly within the muscle cells, making it immediately available for short, high-intensity efforts. The catch is that this anaerobic fuel injection system gives your muscles only about 10 to 15 seconds of high-octane energy before the lactic acid system kicks in to continue providing you with the energy needed for up to two more minutes of high-intensity output before you become anaerobically fatigued and start breathing hard because you need oxygen. At this point, your body switches from the anaerobic energy system to the aerobic energy system, and your training starts to become a conditioning session. This makes the ATP-PC system a critical component of acceleration and speed (as opposed to endurance). One of the great features of the ATP-PC system is that PC can be quickly resynthesized by the cells, and there are no fatigue-causing by-products created in the chemical reaction. This means that incorporating a relatively short period of recovery into your training bouts between efforts allows you to refresh this system and prepare your body for another short burst of intense output.
Typically, your maximum capacity for an all-out effort at or above 90 percent is about 20 to 30 seconds. After that, the ATP-PC system is depleted, and you will start dipping into your lactic acid system to keep the engine revving (refer back to figure 2.5 in chapter 2). How much of each of these two anaerobic energy systems you use depends on the intensity and duration of the effort involved, but they will both need to be replenished before you can do another all-out effort.
For high-intensity efforts above 90 percent, a good work-to-rest ratio for metabolic recovery is between 1:10 and 1:20 (e.g., 10 seconds of maximum effort should be followed by at least one to three minutes of low-activity rest). At a minimum—for more moderate work levels—you should apply a ratio of 1:4. To put this in perspective, elite sprinters will commonly walk around the track for as much as five minutes or more before attempting another max-effort sprint. While this might seem like an eternity in coaching or competition minutes, metabolic recovery is not a chemical process that can be rushed. You can’t eat, drink, or foam roll your way back to a topped-off ATP-PC fuel tank. While a periodized training program can eventually improve your capacity for workload and shorten your recovery times, there are biological speed limits for the chemical reactions of metabolic recovery. That said, metabolic (and neural) recovery cycles should include some very low-intensity movement, such as walking. In addition to alleviating fatigue and allowing your anaerobic energy systems to replenish, low-intensity movements help your body stay warm and flush out some of the metabolites that accumulate during high-intensity efforts.
Neural recovery also involves replenishing your body’s chemistry reserves, but, in this case, instead of topping off your energy pools, it’s about topping off your neurotransmitter pools. Movements that involve high levels of complexity and intensity require an unfathomable number of chemical reactions happening in a precise sequence at precise volumes and ultraprecise rhythms. As previously mentioned, one of the many paradoxes of speed is that it’s less about quickly turning muscles on than it is about being able to quickly turn them off. The ability to fire superfast pulses of distal and proximal stiffness is what makes elite sprinters (as well as jazz drummers, world-class fighters, and professional golfers) elite. True speed comes from the ability to rhythmically turn the system off quickly—that’s how you achieve a fast punch, kick, or throw. From a biomechanical standpoint, a signaling network in the nervous system initiates muscle contractions and creates action potentials using a cascade of chemical reactions (sodium potassium and acetylcholine) in the synaptic cleft—the junction between the nerve and the muscle. When acetylcholine fills this gap, it fires an action potential that causes the muscle fibers to contract.
In simple terms, the more of these gaps that flood with acetylcholine, the more forceful the muscles will contract relative to their capabilities. After the muscle fibers contract, an enzyme called acetylcholinesterase breaks down the acetylcholine and turns the muscle off by eating up the acetylcholine—like Pac-Man. Of course, when I oversimplify a complex neurological process like this, it sounds like it takes a lot of time. The reality is that these chemical reactions happen in a rapid-fire series of transmissions across your body in the space of milliseconds. And when you’re moving with high levels of intention and force, these chemicals get depleted. Even though you may not be doing something for a long period of time, when you do it with full intensity, your neurological chemistry for nerve conduction is being spent because you’re opening those valves all the way up. And when you do that multiple times within an exercise bout, your nervous system gets tired. This means your reserves of acetylcholine and acetylcholinesterase need to be replenished if you want your nervous system to be operating at full capacity for the next effort.
According to Dalcourt, a good work-to-rest ratio for neurological recovery is approximately 1:6. For example, if you have an athlete do a series of three hang-clean reps with full intention over the course of 30 seconds, the athlete should take around three to five minutes to neurologically recover by walking around the gym, breathing deeply, and chalking their hands before trying again. Also, you don’t want them to do things that tax their nervous system. The goal is to let those neurologic chemicals replenish without letting the tissues get cold.
While the need to integrate metabolic and neural recovery cycles within training sessions is fairly well known, one strategy that is often overlooked is in-bout fluid recovery. In this case, fluid recovery isn’t about staying hydrated (which is obviously important); it’s about facilitating fluid recovery in the localized tissues. When you do something intensely—whether it’s sprinting for 40 yards (37 m) or throwing a fastball over and over—limb velocity is high, muscle contraction rates are high, and your mental intention is high. This violent contraction of muscles causes a change in the osmotic pressure gradients of your fascia, muscles, and other tissues. Basically, when you flex your muscles really fast over and over, you push water and other fluids—including blood, lymph, and interstitial fluid—away from those structures. Over the course of an extended training bout (above 30 minutes), those tissues will start reaching a dehydrated state. This is especially significant for the connective fascia tissue. As discussed in chapter 3, fascia tissue is more dynamic and resistant to compression when the extracellular matrix has more bound water in it (when H2O molecules bind to sugar receptors in the tissue). But, if the fascia tissue is squeezed intensely over and over again, those H2O molecules get pushed away. This reduces the fascia tissue’s capacity to resist deformation and tears, which both reduces performance and increases injury risk. High-velocity contractions also make it harder for blood to get in, thereby limiting the amount of oxygen being delivered to the muscles and inhibiting the muscles’ ability to contract. All of this means that including fluid recovery techniques in training bouts that last longer than 30 minutes is essential for maximizing returns.
According to Dalcourt, a good work-to-rest ratio for in-bout fluid recovery during longer workouts is approximately 3:1 (i.e., for every 30 minutes of work, you would need 10 minutes of fluid recovery). “With metabolic and neural recovery, you want to avoid revving the engine beyond a low idle because you don’t want to use up the energy stores or neural chemistry,” says Dalcourt. “But, with fluid recovery, you want to do some foam rolling, you want to use compression garments, and you want to do some rub-and-scrub or massage techniques that push fluid back into where it was pushed out. Those fluids were pushed out by pressure gradients and osmotic flow. So the idea is to push them back into that area by reversing the pressure gradients. That can be achieved through things like self-myofascial release, foam rolling, compression garments, and vibration guns.”