Sprinting is laced into our DNA. It’s part of who we are as a species and represents one of our most primal instincts. Unfortunately, sprinting has fallen off the radar for most people because it’s no longer a requirement for survival. We don’t have to chase down our food or flee from predators on foot. Thus, it tends to take a backseat for everyone but competitive athletes.
While you no longer need to sprint for daily survival -- and though it’s physically taxing to perform -- sprinting doesn’t have to be reserved solely for athletes. Everyone can and should sprint because it’s one of the most powerful adaptive tools we have. Our physiology responds exceptionally well to sprints. When structured properly, sprinting builds muscular strength and power, improves the health of bones and joints, drives metabolism and fat loss, increases oxidative capacity and boosts brainpower.
Build Strength and Develop Power
When it comes to getting stronger, most people focus on lifting heavy weights, and for good reason. Heavy deadlifts and squats are going to do more to develop maximal strength than just about anything else, but there are many different kinds of strength.
The central nervous system is king when it comes to generating force, and motor units are how they accomplish this. A motor unit consists of a neuron (a messenger wire coming from the brain) and the specific muscle fibers it innervates (the muscle receiving the message). Some of these motor units are high-threshold (strong and powerful) and some are low-threshold (not so strong and powerful). In order for any of these motor units to fire, your brain has to tell them to.
When generating large amounts of force, you want to activate your highest-threshold motor units -- and you want to activate a lot of them. But the number and type of motor units recruited depends on the intensity of the effort. So just going for a light jog isn’t going to tap into those higher-level motor units. Rather, you need to be operating at a near-maximal intensity level, and sprinting trains your body to recruit the highest-threshold motor units you have.
But there needs to be a balance. On one side there’s strength, on the other there’s speed. In the middle lies power (a combination of force and velocity). Sprinting contributes the most to the speed side, but as the great Canadian track coach Charlie Francis said, training anywhere along the spectrum makes improvements everywhere. So sprinting helps you tap into your highest-threshold motor units, which gives you the capacity to generate more force and power in everything else you do.
Give Your Bone Health a Boost
Bones require stimuli to remain healthy. In order to initiate bone growth, some form of mechanical loading has to be present, and that load must be greater than a previous stimulus in order to stress the bone. Once the bone has been adequately stressed, osteoblasts (cells that generate new bone cells) will migrate to the stressed region and begin forming new bone. The key factor is the magnitude of the load. If the load isn’t great enough, no adaptation will occur. And, yes, sprinting places a very large load on the bones via ground-reaction forces that reach two to five times a person’s bodyweight (depending on the caliber of the sprinter).
Train Your Energy-Development System
Like a car, you’re only going to be as good as your engine and the fuel it runs on. For your body, that fuel is ATP, and your body has two ways to generate it -- the alactic and aerobic energy systems. The alactic system is your short-term energy supply, responsible for driving activity in the five- to 12-second range (anything that involves speed, power and strength), while the aerobic energy system is your long-term energy supply that drives any type of long-distance activity.
The aerobic system is also responsible for replenishing your alactic system. For example, after running an eight-second sprint, if you want to recover quickly to run another one, your aerobic system drives that recovery. Sprinting does two big things for us from an energy-system perspective: It improves the rate at which you can produce ATP, which improves speed, power and strength; and, when managed appropriately, it improves oxidative capacity because the aerobic system helps you recover between sprints.
How Hormones Affect Body Composition
Sure, working out helps you look better naked, but body composition depends largely on your hormones and the hormonal response you have to training. In particular, we focus on catecholamines, testosterone, growth hormone and insulin-like growth factor because of their impact on metabolism, fuel utilization (burning fat versus burning glucose) and protein synthesis (building muscle). Your body has a minimum threshold that must be crossed in order to activate this desired hormonal response. While lifting heavy weight accomplishes this, so does sprinting. High-intensity effort is crucial when it comes to optimizing your hormones, body composition and metabolism.
Incorporate Sprinting Into Your Training
Before you get started with sprinting, it’s important to note that it’s incredibly fatiguing for your central nervous system. As opposed to local muscular fatigue (having sore biceps the day after an arm workout), which doesn’t have wide-reaching effects, central fatigue affects your entire system. If not addressed appropriately, you’re setting yourself up for overtraining and the possibility of an injury. Also, sprinting is absolutely not meant for people with existing injuries. If you’re beat up, in pain or struggling to move around, consult your doctor or physical therapist before you start sprinting.
If you’re ready to get started, here are five tips to help you fit sprinting into your routine:
1. Start slowly. If you haven’t been running sprints, don’t begin them by going all-out. Work your way up gradually over the course of a few weeks by spending a week at 70 percent of your max, a week at 80 percent and a week at 90 percent.
2. Run for at least six seconds. Each sprint needs to be between six and 12 seconds to appropriately target the right energy system and motor units.
3. Make sure you fully recover. Most people have never done a true sprint session because they don’t rest long enough. In order for sprint training to work effectively, you have to give yourself enough time to recover completely between reps. If you have a heart-rate monitor, wait until your heart rate drops back down below 120. If you don’t have a heart-rate monitor, rest three to six minutes between sprints. It’s not uncommon for world-class sprinters to rest anywhere from 10 to 20 minutes between maximal-effort attempts, so take your time.
4. Perform at least four reps. The number of sprints you perform is going to be dependent on many factors. For example, what’s your current fitness level? What are your training goals? How much and how hard are you training other fitness qualities? Where are you in your competitive season? If you can’t answer these questions by yourself, you might want to hire a coach. But, generally, you want to aim for four to 12 reps, with longer sprints having fewer reps and shorter sprints having more reps.
5. Sprint at the beginning of your training session or on a separate day. Sprints are incredibly taxing, so they either need to be included at the beginning of your training session or on their own day. Either way, make the following day an active recovery or rest day to account for the high levels of CNS fatigue that accompanies sprinting.
While sprinting certainly isn’t for everyone, you won’t know until you try. It’s without question one of the best exercises you can be doing. And when done properly it brings tremendous benefits. If you have any questions regarding sprinting, post them in the comments below. Happy sprinting!