Stress can be good for runners?

When you run, your body repeatedly impacts with the ground and one body part presses on, pulls on, pushes against, or tends to compress or twist another body part.  Do too much and your body will succumb to the stress of running with an overuse injury.  Perfect your training regimen and you will be rewarded with higher levels of performance. 

The objective of training is to remain below the limits where stress becomes damaging, but to approach our individual limits.  The overload principle of training is to train up to your body’s threshold.  Get the formula correct and your body will react to stress by physiologically adapting to it.  Let your program stagnate or drop off and what was once stress, no longer effects a change.  So, running as a stress becomes a bit of a balancing act.  In order to adapt to physical stress, it must be adequate to stimulate a change, there must be enough down time to recover, the training must be varied, and you must be properly nourished. The time required for your body to change is not something that can be altered.

The following are well studied and documented changes your body will experience with training:

• Increased efficiency and performance of the nervous system 
• Increased intramuscular energy stores
• Increases in muscle fiber size and strength
• Increased efficiency and functioning of the endocrine system
• Improved cardiovascular responses to running
• Increased blood volume
• Increased ligament and tendon strength
• Increased connective tissue surrounding muscle fibers
• Increased bone mineral density
• Increased capillary density

Most of the running related injuries seen in physical therapy are related to overtraining.  Most commonly, we see tendon injuries of the achilles and other ankle tendons, the iliotibial band, quadriceps, and hamstrings.  When your body adapts to the stress of running, the muscle changes first.  You get increased recruitment of the muscle for much more rapid and efficient contraction.  The blood supply and energy stores of the muscle increase.  Muscle size and strength increases next.  Muscles adapt in a matter of weeks.  The tendon is the muscle’s attachment to the bone.  A tendon does not adapt as quickly as muscle.  So, early into training tendons experience the stresses of running plus the increased force from stronger muscles pulling on them.  They do not receive a good blood supply.  The tendons will require months to adapt.  This is why it is essential to follow a structured schedule of progression and allow adequate recovery with your training.  Given that, the tendons will get thicker, denser, and more resilient.  A thicker and denser tendon will have a higher threshold to stress and lower risk of injury.

Recommendations:

• To increase your performance with running, you must run.  The specificity of training principle indicates that your body will best respond to exercises that replicate the activity you intend to improve.
• Work with a running trainer or coach.  There is no good substitute for experience and knowledge.  One recommendation is www.thebostonrunningcenter.com, but there are many good coaches out there.
• Follow a program specific to the race you intend to complete.  One resource is www.halhigdon.com.
• Vary your training.  The overload principle indicates that you must operate beyond your customary intensity.  Be sure to incorporate hills and speed training when appropriate.
• Allow yourself adequate time to recover from a heavy training session.  Knowing what is adequate comes with experience.  A running coach or trainer can help with that.  All of the established programs consider rest and recovery.
• Never overload sore muscles or tendons.  You will recover with time unless you crossed that threshold into overtraining.
• You must increase your stretching significantly to counteract the tension that will develop with thicker, denser, and stronger muscles and tendons and the increased connective tissue that will grow around your muscle fibers.
• Make sure you are getting enough sleep.
• Nourish your body with essential nutrients.

 So, remain injury free by adding the right amount of stress to your running program!