myofascial trigger points

During a massage session, some of you may have noticed that I regularly refer to ‘knots’ and ‘sore spots’ in the muscle. This is known as myofascial trigger points (MTP).

MTPs are hyperirritable spots located in a taut band in the muscles. The taut bands are localised bands of hardened muscle within the softer muscle, that run parallel to the muscle fibres. The theorised cause of taut bands states that muscle injury can lead to excessive release of acetylcholine, stimulating excessive release of calcium in the muscle and the subsequent shortening and sustained contraction of the muscle fibres.

These areas can be painful on palpation and elicit a local twitching of the muscle as the taut band rapidly contracts as a result of the manual stimulation. MTPs in the muscle can result in weakness due to the reduction in contractile forces, as well as irregular recruitment and activation patterns in the muscle during movement.
 
Causes:

• Muscular overuse
• Eccentric contraction with unconditioned muscles (e.g. high workload with a young horse)
• Excessive eccentric contractions (long period of intensive exercise e.g. jumping for hours, asking the horse to perform advanced dressage movements repetitively).

 
Eccentric contractions are high-power contractions, where a muscle lengthens as a result of external force. This requires a vast amount of muscular effort.
 
Commonly affected muscles:

• Pectoral muscles
• Brachiocephalicus
• Triceps
• Neck paraspinal muscles
• Gluteus and hip muscles
• Muscles in the thoracolumbar and sacroiliac region.

 
This essentially means that several or even just one session of intense training for your horse may lead to the development of these irritable painful trigger points in the muscle and, if not resolved, can become increasingly uncomfortable, lead to referred pain in other areas of the body (as the affected muscles may ‘shut down’) and your horse may struggle to cope with training.
 
Typically, because these areas are painful, your horse may show behavioural signs during riding as a response and their performance may decrease as they are unable to effectively recruit the right muscles, especially if there are several affected muscles. Aversion behaviours are common in horses with MTPs, for example, when your horse is reactive to the girth being attached. This is because the girth will result in uncomfortable pressure on MTP, eliciting a response from the horse.
 
Trigger point therapy during a massage session can help to relieve and resolve these sore spots and your horse will start to feel much more comfortable and ready for the demands of training. It is important to remember that tension and MTPs can develop very quickly (from just one intense training session!!) and so regular maintenance massages are crucial in keeping your horse in top form and feeling their best.
 
Interval training is also a good way to allow your horses muscles to recover and rest during a training session, and is less likely to cause fatigue. I would recommend (and practice with my own horses) a break every 15 minutes during your training session for 5 minutes of walking on a long rein so the muscles can stretch. This may help to prevent the development of MTPs but this may not always be avoided.


http://www.revistas.usp.br/bjvras/article/view/164351/161980