How do you warm up for exercise?
Conventional wisdom advocates for stretching and light cardio. Before every football practice and game, I started with a jog around the field and assumed my position in the lineup for team stretches. You will find a similar schedule for most team sports played on a field.
In the physical therapy clinic, patients are often advised to jump on the stationary bike or treadmill for a six to eight-minute period, cycling and walking at low intensities to prepare the body for the session. Other sports — such as gymnastics, golf, weight lifting — may use sport-specific tasks at gradually increasing intensities.
Which is the best approach — stretching, generic activity, or sport-specific movements?
The case for stretching
The goal of a warm-up is to prepare the body for the demands of the specific activity. Moderate and high-intensity performance requires high-energy phosphate bioavailability. This is achieved by increasing muscle temperature.
This is where stretching falls short.
Stretching does not create enough metabolic activity to genuinely warm up the muscles or body as a whole. The target of improving flexibility is not valid as a warm-up either.
The brief, minimal increase in flexibility with stretching is not necessary for sporting events. No gymnast relies on the short and minimal flexibility gains from stretching to complete their routine. Flexibility is gained over years of task-specific movements, changing the nervous system's protective responses to movement. Muscle length takes time to change for a sustained period.
But what about dynamic stretching? Could it be a method of improving metabolic activity? This is closer to low-intensity cardio than stretching. The repeated muscular contraction ramps metabolic activity and generates heat. This heat contributes to tissue adaptations such as increasing muscle extensibility and thus becomes a dynamic warm-up.
Research supports dynamic warm-ups for enhancing performance and minimizing injury occurrence. We will get more into the nature of dynamic warm-ups — generic vs. task-specific — later.
I would be remiss if I didn’t mention foam rolling. A recent meta-analysis (pooling multiple studies to create a larger pool of data) found foam rolling prior to athletic events generated small improvements in sprint performance and flexibility, while jump and strength performance changes were negligible (jump slightly worsened).
A momentary improvement in flexibility is not the same as a warm-up. Improvements in flexibility can be achieved with dynamic activity as well but with the added benefit of increased metabolic activity. That leaves us with improvements in sprint performance, a task needed for many sports.
Upon closer review, this improvement is so small you may not even notice it. For elite sprinters, a 0.3% improvement is the smallest amount of change they would be able to detect. For the average individual, there is greater variability between runs due to inconsistencies with performance. A 0.7% difference in sprint speed is likely to occur by chance. These results were only seen in two studies as well.
It should be noted, the act of foam rolling can involve planking, a challenging task that may increase metabolic activity. The mashing of muscle tissue may not matter as much as maintaining a contorted body position over the roller.
We must also consider the power of the placebo effect. This is the most likely cause of improved performance following foam rolling and stretching. Many athletes swear by a specific pre-game routine. If your routine is altered and injury or poor performance follows, the disrupted routine is blamed. This is an outcome bias but it doesn’t matter.
The mind is powerful. If stretching is enjoyable and you feel more mentally prepared prior to an event by doing it, then stretch away. But it shouldn’t be the only form of a warm-up.
The case for generic activity
If you watch the pre-exercise routine of most gym-goers, it involves some form of swinging warm-up. Arm swings, trunk rotations, and leg swings are go-to warm-up techniques for many people preparing to exercise. They are favorites on the driving range. These strategies fall squarely into the dynamic stretching category mentioned earlier.
Another popular method of warming up is the warm-up jog. Anyone who participated in organized team sports is aware of the pre-practice ritual. A warm-up lap around the field followed by team stretching.
As our bodies work more efficiently at higher temperatures — before the level of heat stroke — it stands to reason these warm-up techniques would help. But efficient is a vague term. What does a mere temperature increase facilitate?
Research suggests power output — how quickly you can produce force — may be enhanced 2–5% after a 1 degree Celcius increase in muscle temperature. Those improvements can be achieved without inducing fatigue. Generic movements are enough.
If warming the muscles is so effective, can you simply apply hot packs or crank the heat in the car ride to the gym? Unfortunately, those techniques are not effective at warming muscles an appreciable amount. You will be left with a smelly car and sweaty clothes without the performance gains.
Keep in mind, warm-ups don’t last forever. You need to immediately exercise as the effects on body temperate last only 15–20 minutes.
So, we have established movement is good for warming up the body. The question now is whether specific movements are superior to general movements.
The case for sport-specific movements?
“Warm up to throw, Don’t throw to warm up” — Joe Breen, Director of Baseball Operations, RBI Baseball Academy
Joe Breen isn’t the only baseball coach who shares this sentiment. It isn’t restricted to baseball either. Should you perform a low-intensity version of the task you are about to do as a warm-up?
We believe — I say believe because research is constantly evolving — warming up the body improves power output by increasing the turnover of ATP (our body's source of energy). As power is needed for most sporting activities, this is one of the primary benefits of a warm-up. Another is reducing injury risk (more on that soon).
Task-specific movements, such as squatting and running, have been shown to improve max voluntary contraction by 12%. In this study, however, running was just as effective.
Another consideration is the phenomenon of post-activation potentiation (PAP). When proceeded by maximal or near-maximal short-duration exercise (such as jumps or sprints), muscle performance experiences a temporary boost in performance. The nerves are primed to respond more quickly for strength and power-based tasks.
Before a sprinter enters the blocks, you will often see them perform a couple of max-effort jumps or short sprints to prime the body. Powerlifters benefit from final warm-up sets being in the 60–84% of their 1RM range. Even an opening lift for a powerlifter or weightlifter straddles the line of improving subsequence performance through PAP and diminishing it through fatigue.
The optimal window for improved performance through PAP is about 7–10 minutes, but it can last up to 18. So, if you are performing a 90-minute soccer game, PAP isn’t the mechanism to focus on. If you are a baseball player, the warm-up swings with a heavy bat may improve your power output.
When comparing specific and general activity, this is where the separation occurs. General activity is great for warming up the body, which will improve performance. If you want to maximize performance, however, task-specific movements should follow.
Research assessing aerobic sports such as running, cycling, or swimming show short, intense bursts of the specific movements after a generic warm-up are the best strategies for enhancing performance.
For team sports such as football, soccer, and rugby, research shows task-specific activities are superior at neural priming, improving neuromuscular activation. The body is better prepared for the specific demands of the sport. The neural mechanisms are key for more than performance.
I won’t get into the details of injury prevention. Just know injury prevention is complex. I do think it is worth noting the role of warm-ups in injury prevention. Current research is pointing to task-specific warm-ups being a key strategy for reducing injury risk.
Multi-modal warm-up programs, like the 11+ or FIFA 11 program, are currently the best bet for the prevention of ACL tears. The warm-up focuses on strength, power, endurance, and balance (no stretching).
A 2017 study included a sample of 6,344 soccer players. Of the half who completed the FIFA 11 warm-up protocol throughout the season, 24% suffered injuries. In the half who completed general warm-ups, 40% suffered injuries. The results mark a 30% reduction in injury risk through the use of the FIFA 11 protocol.
The results don’t suggest the FIFA 11 should be used by all athletes, rather, task-specific movements should be incorporated into warm-up activities.
Throw to warm up, but do it after a general warm-up to prepare the body for throwing.
Don’t forget about the psychology of warm-ups
One part of my job I’ll never learn to love is the pre-match warm-up. I hate it with every fibre of my being. It actually disgusts me. — Andrea Pirlo
For some (such as Andrea Pirlo) the warm-up is a ‘have to’ routine, but for others, it is a ‘get to’ experience. We shouldn’t overlook the psychological influence of warm-ups.
Looking at the research, dynamic, task-specific warm-ups are the best strategy for preparing the body for competition. These movements should serve as the foundation but they don’t need to be exclusive. Stretching doesn’t induce metabolic benefits but it may have large psychological benefits.
Many athletes use the warm-up period to psychologically prepare for the upcoming event. They may perform meditation to calm and clear the mind or preparatory arousal to “psych up.” Visualization exercises are often used to narrow focus and improve self-confidence. Research has shown visualization exercises can improve cognitive and physical performance in subsequent sporting events.
Team stretching carries the benefits of building comradery among teammates, providing time for coaches to discuss strategy with athletes, and allow for visualization. The value of stretching is not limited to the act of stretching the muscle.
There may be a placebo effect at play as well. Athletes are creatures of habit. They thrive on routine.
Stretching is not creating harm. As long as it is an add-on, not a replacement of generic and task-specific movements, it can be incorporated into the warm-up.
That is why I ask all of my patients how they like to warm up before starting a physical therapy session. Individualization is important. When we warm up, we aren’t only warming up the body, we are warming up the mind as well.