Posts tagged endurance athletes
Does Endurance Training Maintain Muscle Mass and Strength?

Triathletes have no shortage of aerobic exercise each week as they train for all 3 components of their sport, but often what they leave out is strength training.  Strength training has been shown to reduce injury risk and improve performance in swimming, cycling, and running.  The impact of this training is most noticeable in the athlete’s economy during each component of the event allowing them to sustain a higher power output, at a relatively lower level of aerobic capacity, compared to individuals who do not strength train.

In an older study authors examined the impact of strength training on muscle strength and muscle size among athletes who completed resistance training, running, or swimming for at least 10 years (Klitgaard et al. 1990).  The authors reported older athletes who completed resistance training had muscle cross section area and strength similar to younger sedentary individuals.  Surprisingly, the subjects who only competed running or swimming activities had similar muscle cross sectional area and strength to their sedentary peers.  The authors concluded that the regular performance of only endurance exercise was not able to prevent the loss of strength or muscle size associated with the aging process.

Endurance athletes are encouraged to perform regular strength training to slow the effects of aging and to improve their performance within their sports.  To learn more about how to incorporate strength training into your workouts contact a local Physical Therapist.



Predicting Injury in Runners from the Physical Therapy Exam

We have previously written about the functional movement screen (FMS) and its' ability to predict injury although more recent research has called its' predictive ability into question.  The highest quality research on the FMS has occurred in NFL athletes or those training for the NFL combine.  The research demonstrates the predictive value of these tests may be less powerful in endurance athletes.  As the diagnostic utility of these 7 tests falls it requires the clinician to incorporate other data from the subjective and objective examination to determine an athlete's injury risk.  An important aspect of the FMS that should not be overlooked, regardless of an athlete's sport, is their emphasis on movement quality.  Poor movement patterns may be secondary to a loss of joint mobility, strength, coordination, or balance and can lead to injury if not corrected.  In a runner, a poor movement examination on the treadmill may indicate the need for gait retraining by a Physical Therapist.  

A recent article by Hotta et al. examined the ability of the FMS to predict injuries in 18-24 year old competitive male runners (J Strength Cond Res. 2015).  Each athlete was scored on the 7 examination items during the preseason then followed through the running season to determine the predictive ability of these 7 tests on the development of future injury.  Prior authors have reported a score of less than 14 indicating poor movement patterns is predictive of future injury.  Hotta et al. found this composite score had a low predictability for running injuries.  Conversely, two tests including the active straight leg raise and deep squat had high predictability for running injuries.  A runner with a poor score of these tests had a 10 times greater risk of injury during the season.  

This article continues on prior research indicating the complete 7 tests may not be appropriate for all sports and athletes.  Instead, specific examination tools like the overhead squat can be combined with gait analysis and other running specific examination tests for a more predictive injury screening.  

Heart Rate Variability and Training vs. Overtraining

Aerobic exercise has a tremendous impact on our morbidity and mortality due to its' ability to positively impact our emotional, mental, and physical health.  In particular, the cardiovascular system undergoes dramatic improvements in response to aerobic exercise.  These benefits are noted in many of the variables we track clinically including blood pressure, VO2 Max (aerobic capacity), respiration rate, and heart rate.  Heart rate changes are well documented in the literature and include a decreased heart rate at a given level of exercise in a trained versus untrained individual.  This is due to the cardiovascular system becoming more efficient in its' ability to deliver a higher volume of blood carrying nutrients and oxygen to the body.  This efficiency is also noted as a lower resting heart rate in trained individuals.  Recently in the literature articles have discussed heart rate variability as a clinical measure of training in endurance athletes (Meeusen et al. Med Sci Sports Exer. 2013).  

Heart rate variability is an indirect, clinical evaluation of the heart's rhythm due to the influence of autonomic nervous system.  This physiological event is described as the time interval between heart beats.  A low variability heart rate would have consistent durations between beats (increased sympathetic aka flight or fight influence) whereas a high variability would reflect inconsistent, changing durations between beats (increased parasympathetic aka rest and digest).  Tracking heart rate variability on training and rest days may allow clinicians and endurance athletes to determine if the aerobic training is having a positive or negative impact on the athlete.  

An athlete who is overtraining (weeks to months) or overreaching (days to weeks) is caused by an accumulation of training with inadequate rest which results in short term or long term decrements in performance or physiological markers.  These athletes would demonstrate maladapting responses to cardiovascular exercise including decreased performance, overuse injuries, and emotion or mental stress or fatigue.  These athletes have been shown to have a higher resting heart rate (>4-5 beats per min), a lower maximum or training heart rate (<7-8 bpm), and low heart rate variability (Bosquet et al. Br J Sp Med. 2008).  Limitations into this research show large variability between athletes, testing positions, and variability within normal heart rate ranges.   

In short, heart rate variability is a promising tool, but further research is needed to improve the consistency of the research.  Tracking heart rate may help complement our other clinical tests and measures, as well as, the athlete's subjective report on determining if an athlete is overtraining.  Other key measures to track include training performance, sleep quality and quantity, diet, mental alertness/fatigue, and mood.