Most coaches intuitively understand that a training exercise won’t improve sport performance unless the exercise is similar to the sport. But, what does it mean to be similar? In the science of training, the similarity between an exercise and the sport is called specificity.

By achieving specificity, we guarantee a more “direct” relationship between the exercise and sport performance. In other words, the exercise will have a positive influence on sport performance. The degree to which an exercise influences sport performance is called training transfer.

Once we find an exercise that is specific and leads to training transfer, we then need to progress the exercise. It is well understood in the science of training that every exercise abides by the “law of diminishing returns”. In other words, the more you do something, the harder it is to improve that something. The “law of diminishing returns” is why youth players and young professional players make larger improvements from game-to-game and season-to-season compared to older players. It is much easier for an Under 17 player to improve than a 29 year old professional player. First, because the Under 17 player has much more “room for improvement”. Second, because the 29 year old has been exposed to almost every imaginable training stimulus. He has effectively “squeezed” all the juice from the orange.

The Law of Diminishing Returns

This point is often ignored in sport. If you read between the lines, you can see that nearly anything you do with a youth player will make them better. An under 16 player can do nearly any type of strength training, from Nautilus Machines to Physio Balls, and make improvements. However, what is often misunderstood, is that these “gains” are very short-lived. In fact, the only time that the law of specificity doesn’t apply to strength training is with beginners. Unfortunately, many coaches fail to acknowledge this fact. As a result, they develop a false association between the strength training exercises they use with youth players and universal performance improvements. They ignore the fact that the reason for the performance benefits is not the exercises, but the characteristics of the people doing the exercises.

Nevertheless, we are still interested in improving players, regardless of their “training age”. Once we have satisfied the principle of specificity and the principle of training transfer, we then need to find ways to progress a player through an exercise. In order to make progress, a high demand must be placed on the player. This demand is typically referred to as a training stimulus. In order to make progress, the training stimulus must exceed previous training stimuli. This is known as overload. If the training stimulus is too large, then the player will be over-overloaded, which can result in injury. If the training stimulus is familiar, then the player will be underloaded. If the player doesn’t train at all, then he will be under-underloaded. This can also lead to injury.

Overload isn’t solely achieved by doing more. It can also be achieved by doing different. Changing the exercise is also a means of overload. In the science of training, this is known as variation. In many ways, variation and overload are two words for the same idea. In order to make progress, we must do something we haven’t done before. This is traditionally achieved by adding more load to the bar. However, it can also be achieved by altering the exercise in certain ways or doing a different exercise entirely.

Of course, not every player is the same. Within a professional team, you will have 30 players with 30 different characteristics. Older players, younger players, previously injured players, fresh players, fatigued players, etc. Because of these differences, applying identical training stimuli to each player will not result in identical training responses. Some players will be over-overloaded, some will be overloaded, some will be underloaded, and some may be under-underloaded. This makes planning training extremely difficult and, frankly, unpredictable. Nevertheless, these individual differences must be taken into account. This is called the principle of individualization.

Overloading a player one-time is not sufficient for progress. If only it were that easy. Imagine if we could reach our goals by going for one run, or working out at the gym one time. Unfortunately, that’s not how it works. Performance improvements take time. There is a reason why teams are given 6-weeks for pre-season. Because improvement takes time, we need to systematically apply overloads and underloads over a given period of time. In the science of training, this is called periodization. Periodization is the planning of all training sessions and matches. Coaches use periodization as a tool to organize and apply training overloads and underloads in a way that minimizes ‘damage’ and maximizes performance.

Wouldn’t it be nice if the results from a periodized 6-week program lasted forever? Well, they don’t. This is called the law of reversibility. Just like a gallon of milk, performance improvements have an expiration date. If players fail to stimulate certain performance characteristics frequently enough, then performance will suffer. Eventually, milk goes bad.


In this short post, we defined a few training principles. These training principles apply to football action training, basic action training, movement training, conditioning, and reconditioning. In other words, they are universal rules that help us develop and apply training protocols to our players and teams. Ignoring these training laws can have major consequences. At best, we will be wasting our time. At worst, players will become injured.

The training laws discussed in this post and that will guide future posts were:

Specificity – whatever we do in training should be similar to what we have to do in the game. This law has many layers which will be discussed in future posts. This is an extremely important law for understanding the remainder of our series on football strength training.

Training Transfer – exercises that satisfy the law of specificity will have a more guaranteed chance of transfer. Exercises that are not specific will be more, or less, a waste of time.

Law of Diminishing Returns – the better you get at something, the harder it is to keep improving. This is why nearly any type of training will work with beginners. More advanced players require a much more thoughtful training protocol.

Training Stimulus – This is the actual training session. Both the content and context. Content like the actual exercise, actions performed, work to rest ratios, total duration, intensity, etc. Context like the training type (football, basic actions, movements, reconditioning, strength training), day of the week, part of the season, proximity to the next match, proximity to the last match, participants (substitute players or first team), etc.

Overload/Variation – This is the term used to describe a training stimulus that exceeds previous stimuli. In other words, the player has to do something he has never done before. If the training stimulus exceeds previous stimuli too much, then the player will be over-overloaded and risk injury.

Underload – This is the term used to describe a training stimulus that is familiar to the player. In other words, the player has to do something he has done before. Sometimes, the load can be too familiar, like laying on the couch for weeks, in which case the player is under-underloaded. After a period of under-underloading, the player will be at a higher risk for injury.

Individualization – Players are different! A 30 year old player that has a previous history of Hamstring injuries will respond differently to a training stimulus than a 20 year old player that has never had a bruise. It is unrealistic to develop thirty individual training sessions, but there are some ways that the overall training session will need to be adapted to suit the individual needs of specific players. Examples of these will be discussed in future posts.

Periodization – One overload session is not enough. Players need to put together a string of overload sessions over a period of time in order to make progress. As a result, coaches need to apply overload sessions to their players in systematic ways. Applying overload sessions every day would obviously lead to over-overload. Applying overload sessions once a month would obviously lead to under-underload. Therefore, an approach must be taken that finds a balance between applying overload and underload sessions in a consistent fashion. This consistency can allow for gradually increasing training stimuli to be applied week-to-week and month-to-month.

Law of Reversibility – Training gains do not last forever. If a performance characteristic is not stimulated by training, it will get worse. Eventually, it will spoil like a gallon of milk. This is why coaching is such a difficult endeavor. First, coaches need to identify what performance characteristics are important (like football ability and football capacity). Second, coaches need to develop a training approach that effectively stimulates these performance characteristics consistently enough to keep them from going bad.