With pain the context is important. This means that in different circumstances we can experience pain or not depending upon the situation. An example would be walking along the road barefoot and you tread on a nail. Ouch! It hurts and you would expect this to be the case as you have just trodden on a sharp object. However, if you were walking along the road and trod on a nail and a bus were to be coming straight for you, the nail would no longer be important and you would run out of the way. The foot would probably hurt later once you had calmed down. The key point is that whatever happens in the tissues, for us to experience a sensation, and that includes pain, the brain must analyse the signals being sent in from the tissues (via the spinal cord) and make sense of the situation thereby creating our perception of what is going on. Even if there is tissue damage, if there is something more important for survival or of interest for that matter, then we do not have to feel any pain despite the fact that danger signals are being sent to the brain. The brain decides.
For Nadal and his foot pain (http://t.co/5NMsXnp), clearly he noted this during the game and felt the need to ask the trainer to take a look. The foot was taped and he continued to play, winning his game on Centre court. There are many examples of sports men and women continuing to play despite injury, especially during crucial games. The brain is quite capable of dampening down the danger signals (sends messages down to the spinal cord) and allowing for continued activity. There are also many stories about battlefield survival with significant trauma or loss of limbs where the soldier reports no pain at the time. Of course phantom limb pain is another example of how we do not need tissues to experience pain.
Generally speaking it is not advisable to continue playing if the activity or sport is provoking pain. Pain is part of a protective response that also includes changes in movement, healing, blood flow and systems in the body looking to restore homeostasis. When something hurts, that pain is telling us to attend to the situation, which Nadal did and managed to successfully override the ‘danger’ or ‘threat’ in order to continue. In his situation, the end goal is to win Wimbledon and I am sure that he will do everything that is required to maintain function at this time and then deal with the consequences when the tournament has finished. At that point a complete treatment and rehabilitation will promote healing, symptom relief, normalisation of movement and control of movement (so important in desensitisation). A total programme should consider the tissue health at one end of the spectrum but also the functioning of the nervous system and other systems that influence pain at the other in order to minimise the risk of recurring problems.
We see many recurring problems that are due to incomplete rehabilitation, noting on-going changes in sensation, intermittent pain, altered control of movement and a lack of full confidence in using that affected area. Tackling these issues with modern techniques based on current neuroscience such as those we use at the Specialist Pain Physio Clinics brings the athlete back to full fitness and function with confidence.