Blog By Dr John Cronin
Are you interested in getting players faster by simply warming them up? If so, then a recently published study by Bustos at al (2020) from the Journal of Strength and Conditioning Research will interest you . It analyzed if players could get faster with wearable resistance by using it in their warm-up. They showed that a group using wearable resistance (WR) in a warm-up improved speed and leg power as compared to the unloaded control group. In this article, I want to share the program that improved speed performance and some thoughts around warm-up, that hopefully drives you to rethink the value of a warm-up.
Rethinking The Warm-Up
We think of a warm-up as a means to prepare the cardiovascular and musculoskeletal systems for an event or sport, and we typically adhere to some sort of RAMP protocol, where exercises are chosen to: raise heart rate and muscle temperature; activate and mobilise muscles specific to the event; and potentiate/prime athletes ready for the onset of training or competition. However, WR has brought a new dimension to the warm-up as the results from Argentina have shown, where a group of provincial soccer players that warmed up with WR improved many key athletic qualities (speed, power, and repeated sprint ability) more so than the unloaded control group.
These findings do not come as a surprise, if you remember that wearable resistance is a form of movement-specific resistance training. That is, you use it during your practice whether it be for the warm-up, conditioning, speed session, technical/team run, etc. What defines the technology is that the resistance training is part of what you do, and not separate from what you do. Hence, it’s not surprising that a well-structured warm-up will result in sport specific adaptation. So the trick then is to think carefully about the movement patterns and fitness qualities you want to target in the warm-up.
Warm-Up And SAID
The SAID principle (Specific Adaptation to Imposed Demands) helps us understand why a well-structured warm-up will result in adaptation when using wearable resistance . At the heart of this principle is that the human body will adapt to the stressors placed upon it, whether these be mechanical (muscle, tendon, bone, etc.), energetic (heart, lungs, etc.), neural, etc. So in the case of a warm-up, if we add wearable resistance to certain movement patterns, the body will adapt accordingly. The natural evolution of this principle, is to think carefully about your movement choices that you want to overload and train. The principle of specificity should drive this, and those movement patterns important to your event or sport, are central to movement selection for the warm-up. Apart from this targeted movement focus, you warm-up exactly the same but with WR attached to some part of the body, which was the calf in the Argentine study as shown in the diagram below.
Let’s take the SAID principle one step further by understanding that another important differentiator of wearable resistance is that you’re training movement more so than muscles, which is typical with more traditional gym-based resistance training. Therefore the likelihood of transference of your training into the desired adaptation is heightened. So for example, if you’re seeking improvements in lateral or change of direction ability, you need to ensure that the exercise, drill, or movement selection for your warm-up includes a solid dose of these resisted movements.
Figure1: Diagram of players with and without resistance in their warm-up
If you want to find out about the specifics of the methodology and results then I refer you to the manuscript as referenced at the end of this article. It needs to be noted that the subjects used in this study were sub-elite soccer players who had won the National U17 competition the previous year. The program that effected statistically significant changes in speed was the one that used wearable resistance calf sleeves only. Why calf sleeves? Simply put, the further a load is from the axis of rotation (e.g. the hip), the greater rotational inertia or the greater resistance to angular motion. When loads are further from the axis of rotation, the muscles across the hip and knee must work harder to accelerate and decelerate the limbs. Also from a practical point of view the calf sleeves are easy to slip on and off as required.
The program involved a periodised schedule where load [200 gm (7 oz) to 600 gm (21 oz-1.3lb) per leg] and placement of load [close to knee (proximal) and far from knee near ankle (distal)] were changed over the eight weeks of training (see Figure 2 for an example of proximal and distal loading).
The wearable resistance loading protocol used in the warm-up for the soccer players is shown in Table 1. You can see that players used wearable resistance in their warm-ups 3 times per week, the progressions (load and placement) within the program, and the off-loading every 3-4 weeks. With less well-conditioned athletes, you might consider using wearable resistance two times per week until you think they’re handling the additional overload. Also note that when 600 gm loading was used, 400 gm was placed on the posterior calf and 200 gm on the anterior aspect of the calf.
Figure 2: Proximal (left) and distal (right) calf loading.
Table 1. Periodised 8-week loading program for WR training.
The on-field warm-up program used a typical RAMP approach consisting of 4-6 minutes of low to moderate running exercises combined with active stretching. This was followed by 10-15 minutes of technical drills with the ball and then 5-8 minutes of high-intensity accelerations, decelerations, changes of direction, plyometrics, and sprint exercises. Acceleration and speed were emphasised in the last exercise block. The players were typically in groups of five to six, which meant rest periods of 30-45 seconds between drills. At the end of the warm-up, players removed all loads from the calf and completed the practice with the sleeves on.
Some of the locomotor patterns used in the warm-up are shown in the videos. As you can see from the videos, the warm-up involved sprinting over 10-20m, with many changes of direction. With the SAID principle in mind, it’s no wonder the players experienced significant decreases in their sprint times as they performed resisted sprint training 3 x 8 mins a week. As a side note, many players report that they don’t notice the additional load and in fact Rating of Perceived Exertion (RPE) differs minimally between those using wearable resistance and those who do not. Understand though, if players move these light loads at high velocities, considerable mechanical and therefore neuromuscular overload is experienced. Therefore, resist adding additional load and stick to the program to ensure adequate rest and recovery via a well-planned periodised schedule.
Rethinking the warm-up and its potential to improve athleticism, is worthy of some serious consideration. This is particularly important when we are in-season and time poor, particularly for sports with congested schedules such as baseball, basketball, European soccer, etc. Typically in these situations it is very difficult to maintain “fitness” and detraining occurs. We may now have the means to improve, or at the very least maintain, important athletic qualities in-season—speed, power, stamina, change of direction—by simply engaging in a well-structured warm-up with wearable resistance.
Reference: Bustos et al. (2020). Effects of warming up with lower-body wearable resistance on physical performance measures in soccer players over and 8-week training cycle. Journal of Strength and Conditioning Research. 34(5), 1220-1226.
Acknowledgment: Thanks to Anibal Bustos and Gustavo Metral for sharing information on the training of their soccer players and providing pictures and video material.