Injuries sustained in pre-season training can be viewed in two ways; either as the unavoidable consequences of trying to regain fitness after a short lay-off or as a major disruption to the plans for the forthcoming campaign. Opinions are largely divided on this; with some coaches thinking that minor knocks are ok and accepting that the occasional strain is something that happens in football, while others regard injuries in the pre-season period as totally unacceptable.
To be honest, injuries in pre-season do tend to be unavoidable. You are always going to get them, and in addition to the usual bumps, bruises and strains, there's nearly always a ‘proper' injury that will keep someone out of action well after the opening weeks of the season have come and gone. It's probably no surprise then that Real Madrid have had two players pull out of one of the early sessions in Canada with muscular problems.
There are very few secrets in football these days and when Danilo and Marcos LLorente had to pull out of the session the other day it didn't take the world press longer than two minutes to report it. At first glance I thought that Danilo had suffered a recurrence of his recently-operated on ankle problem but it transpires that the Brazilian defender was forced to come off with a hamstring strain instead. There can't be many worse situations for a player returning from injury than to immediately receive another. Apart, that is, from a recurrence of the original injury which thankfully Danilo is reported not to have.
It's actually quite common for players returning from one injury to sustain another to a different part of the body. There can be a number of reasons for this; and none less than that fact that you often work so hard on the original injury that the area in question becomes stronger than the corresponding area on the opposite leg.
In Danilo's case, as long as the surgery has been successful in the first place - and to be fair it must have been otherwise he wouldn't have been back training - he's likely to have worked on his operated ankle so hard in recent weeks that he'll probably find that's it's a lot stronger than the opposite. This change of load-balance can then mean that other areas of the body that have perhaps not been subjected to the same stresses during rehab as his ankle will have been, are then potentially liable to injury as a result of a shift in the biomechanical load. In this case the hamstring muscles have been the ones which gave way first; likely because during Danilo's ankle rehab the focus throughout will have been on strengthening the lower part of the leg in the rehab sessions.
The body can only cope with high-intensity demands of training up to a point, and if all a player's efforts are being put in to one certain area - such as the ankle for example - it becomes impossible to put that effort into the other areas at the same time and at the same levels of intensity. The latter is the key; and that's often why players come back from one injury and immediately sustain another.
In an ideal world the levels of intensity would be applied uniformly throughout the body; so in other words the hamstrings, thighs and so on would be subjected to work at the same intensity levels as Danilo's injured ankle would have been. However, in the real world, the practicalities are different to the theory and the challenge in rehab to the fitness team is to try to keep that intensity uniform throughout the body. However, tissues will only adapt if they are stressed; and so the focus in Danilo's rehab will have needed to have been on the ankle.
Once the ankle was strong enough to allow him to take part in full training, the rest of Danilo's body will then have been subjected to the uniform high-intensity work along with the other members of the squad; and this is often where the cross-over effect becomes evident when returning from injury. The injured area itself should have healed; but scope then exists for the other area of the body to be slightly less tuned in turn. However, it is generally accepted that this is whole point of ‘pre-season training'; to subject players' bodies to high-intensity work-outs that will ensure that all components of fitness are developed to a high level - and then ‘fine-tuned' towards the specific requirements of football.
The pre-season period is the time when players lay down the foundations in terms of their fitness for the coming season. To go back into pre-season after a summer's break - such that it is anyway - is hard enough without the added complication of going into pre-season training and returning from an injury at the same time. It looks as though Danilo has just been unlucky on this occasion; and provided the hamstring injury is nothing more serious than a minor tearing of a few muscle fibres that will heal in a couple of weeks' time then it's likely that no real harm has been done .