Effect of Warm-up (Jens Bangsbo & Casper Skovgaard) (Patreon)

Warm-up Increases Muscle and Body Temperature:

During exercise, the active muscles produce heat. As the intensity of the exercise increases, more heat is generated. Some of the heat is transferred from the muscles into the blood and is dispersed throughout the body. Thus, exercising with large muscle groups not only causes an increase in muscle temperature but also results in a considerable rise in body temperature. During intense exercise, muscle temperature may rise to 43°C, while body temperature can reach 41°C. Figure 1.1 illustrates what happens to the temperature of muscle and body during 50 minutes with exercise at constant moderate intensity. The muscle temperature reaches a stable level after about 10 minutes. whereas the body temperature is still rising after 50 minutes.

Warm-up Increases Performance:

A rise in muscle temperature increases the ability of the muscles to produce energy during exercise. This is one reason for the improvement in performance observed after a warm-up. Figure 1.2 shows the relationship between muscle temperature and performance on a cycle ergometer during a brief sprint. From the results presented in Figures 1.1 and 1.2, it can be concluded that a warm-up should last for at least 10 minutes for the players to fully benefit from the increase in muscle temperature.

The type of warm-up in football also affects performance. A study of male football players investigated the effect of three different types of warm-up:

1) 3 repetitions of a small-sided game (3v3) with 2 minutes of play separated by a 2-minute recovery period; thus, a total duration of 10 minutes. The size of the pitch was increased from 20x12m in the first repetition to 25x15m in the second repetition and 30x18m in the third repetition.

2) 5 minutes of jogging, followed by a 5-repetition maximum (RM) seated leg press.

3) A"normal warm-up" routine in football lasting approximately 23 minutes, which included general activities, such as butt-kicks, high-knees and air squats, performed at medium intensity for 6 minutes, followed by specific movements (i.e., back and forth sprinting and change of direction) performed at high intensity for 9 minutes. The last part was ball-control activities, such as passing, dribbling and run-throughs, performed at high intensity for 6 minutes.

Results:

4 minutes after the warm-up, the players performed various tests and physiological measurements were carried out. Countermovement jump height improved following the small-sided game (6%) and slightly with the leg-press warm-up (2%), but not after the "normal warm-up" (see Figure 1.3). 

Similarly, agility improved only after the small-sided game (4%) and leg-press warm-up (5%; Figure 1.4). 

Mean 20-meter sprint time improved following the leg-press warm-up when compared to the small-sided game (9% more) and "normal warm-up" routine (7% more). Blood lactate was highest following the small-sided game and "normal warm-up" (see Figure 1.5). Apparently, leg-press and small-sided game warm-up were more effective than a traditional 23-minute warm-up protocol in improving performance. It may be that the "normal warm-up" negatively affected the players' performance due to development of fatigue.

Conclusions:

Thus, it can be concluded that a warm-up of rather short duration can improve performance, and too much high-intensity exercise during warm-up, as in normal football warm-up, may eliminate the positive effect of warm-up.

Warm-up Reduces the Risk of Injuries:

Many injuries occur due to an insufficient warm-up. A cold muscle is relatively rigid and resistant to sudden increases in tension caused by rapid movements. When the elastic components of the muscle are unable to accommodate the external tensions, the muscle will rupture. This is commonly referred to as a "pulled" muscle. Thus, by warming up the muscles and tendons, the risk of injuries is significantly reduced.

Stretching During Warm-up:

The value of stretching during a warm-up has been discussed for many years. Previously it was believed that static stretching (i.e., the position is held for more than 10 seconds) improved performance, but there is evidence that the opposite is the case. Thus, a bout of static stretching has been shown to lead to significant reductions in maximum muscle strength and power. On the other hand, dynamic stretching (i.e., moving while stretching) has positive effects on subsequent performance, such as on force, power, sprint and jump performance. It also increases the range of motion around a joint, which reduces stiffness of the muscle-tendon unit. Nonetheless, the increase in muscular performance is not just related to the improved range of motion but also to the increase in muscle temperature associated with dynamic stretching.

It should be emphasized that some studies have shown no effect of stretching. Thus, the effects of static (5 or 30 seconds, 5 repetitions per muscle group), dynamic (seven lower body and two upper body muscles) and no stretches, performed as part of a comprehensive warm-up program, were examined in team sport athletes. Participants felt they were more likely to perform well when stretching was performed as part of the warm-up, irrespective of stretch type. However, no effect of muscle stretching was observed on flexibility, sprint running, jumping and change of direction compared to no stretching. Thus, this study showed that the inclusion of short durations of either static or dynamic stretching did not affect performance when conducted as part of a comprehensive warm-up program.

Despite the different results from scientific studies, the players may benefit from dynamic stretching to increase range of motion and to enhance sprint, jump, muscle force and power performance.

It has been shown that it is better to use controlled dynamic stretching, rather than ballistic stretching (i.e., dynamic stretching with high velocities).

Summary:

Warm-up does increase body and muscle temperature, leading to elevated performance and reduced risk of getting injured. If the warm-up is too intense, however, the positive effects of warm-up may be abolished. Static stretching longer than 5 seconds should be avoided during the warm-up, as it has been shown to reduce performance. On the other hand, dynamic stretching may increase performance and should be part of the warm-up.

Reference:

- Warm-up in Football: Optimize Performance and Avoid Injuries (2021) - By Jens Bangsbo & Casper Skovgaard.