Posts in performance
High Intensity Interval Training Improves Endurance Performance

Among Boulder endurance athletes many training variables are utilized to promote beneficial adaptations within our bodies.  These adaptations to the cardiovascular and musculoskeletal systems lead to improved future performances in practice and competitions.  One training variable includes interval training where athletes complete portions of endurance exercise at a high intensity followed by a recovery period.  As these intervals are completed, athletes are able to train at this intensity for a longer cumulative duration (multiple intervals) than if they tried to complete the same intensity and duration over a single bout.  High intensity interval training (HIIT) programs, where the intervals are held close to maximum efforts followed by recovery periods, are gaining momentum among endurance athletes.

A recent article in the Journal of Strength and Conditioning research examined the impact of HIIT programs among triathletes (Garcia-Pinillos et al. 2016).  Athletes were timed on a sprint triathlon before being divided into two groups: one continued their current triathlon training and the second continued their training except substituted their run training for HIIT.  Athletes in this group completed 3-4 sessions of HIIT/week consisting of 100m and 400m distances, as well as, 30-120 second run intervals over 5 weeks.  At the end of the 5 weeks all athletes were tested again on their sprint triathlon performance. 

The authors reported improved run and swim performance after the HIIT leading to faster times among the trained group.  This study adds evidence to support the use of high intensity, low volume interval training among endurance athletes. 

Compression Garment's Impact on Running Recovery and Performance

Compression garments including shorts, tights, and socks have gained in popularity among both amateur and professional runners.  Manufacturers and athletes claim improved circulation, recovery, and performance can be found using these products either during or after a run.  As with many products in health, fitness, and performance these claims should be taken with a grain of salt until supported by research institutions.

A recent article in the journal Sports Medicine evaluated the available evidence on the psychological, physiological, and performance effects of compression garments (socks, calf sleeves, shorts, and tights) in runners (Engel et al. 2016).  The authors found moderate beneficial effects for delayed onset muscle pain/soreness and delayed muscle fatigue in athletes wearing compression garments during run.  Additionally, smaller beneficial effects were noted for improvements in running economy and time to exhaustion suggestion these garments may slightly improve performance.  Important to note is the lack of significant effects on sprint, middle, or long distance timed runs or physiologic variables such as cardiac output, blood lactate levels, or body temperature were noted in the review.  

In short, compression garments seem to have their greatest impact on perceived muscle pain/soreness and recovery, but performance effects are small.  

The Impact of Core and Leg Muscle Fatigue on Baseball Throwing Mechanics

As we move into Spring we begin to see our youth athletes return to the baseball diamond often with a sudden increase in practice volume.  The sudden increase in throwing volume, either in the field or on the mound, places the athlete's shoulder and elbow at greater risk of baseball injuries. The greatest risk factors for injury include throwing more than 80 pitches/game, playing baseball greater than 8 months/year, and pitching with arm fatigue. As discussed in our prior posts, an athlete's throwing velocity is driven by their legs strength and power. Athletes with leg weakness are more likely to suffer from progressive changes in performance and increased injury risks.

A recent study in the Orthopedic Journal of Sports Medicine authors analyzed the impact of fatigue on throwing velocity, accuracy, and throwing mechanics (Chalmers et al. 2016). Authors studied 28 elite adolescent (13-16 year old) pitchers as they pitched a simulated game (90 pitches). Each pitch was analyzed for velocity and accuracy while every 15th pitch was analyzed for pitching mechanics. As expected the velocity, accuracy, and mechanics suffered with increased pitch counts. Importantly, the authors showed the loss of velocity, accuracy, and biomechanics were preceded first by core and leg muscle fatigue.

This study adds to the importance of controlling pitch counts and treating the lower extremities in order to improve throwing performance and reduce injury risk.  

Is my endurance training enough to build strength and muscle mass?

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.



Strength Training to Failure

A common question we receive in clinic is how many repetitions should I perform of this strengthening exercise?  Clearly, enough repetitions are needed under a given load to promote beneficial changes within the tissues for improvements in both healing and performance.  Ranges of repetitions range from < 5, 8-12 reps, and >15 reps depending on the intended goals of the exercise and the patient/client's capability.  Another repetition goal gaining popularity is performing the exercise until muscle fatigue/failure regardless of the number of repetitions.  The biggest limitation of this training is sacrificing intensity (amount of weight) in order to perform a high number of repetitions.  A study recently compared the effects of training until failure with higher intensity exercises.  

Looney and colleagues had healthy volunteers squat with 50, 70, and 90% of their maximum squat strength (J Strength Conditioning Research. 2016).  Athletes were assessed for muscle activation during these exercises to determine which level of resistance and repetitions produced the most beneficial environment for strength gains and muscle growth.  The authors results were consistent with the previous literature indicating intensity (higher weights) is more effective than training to fatigue (higher repetitions) for muscle performance.  Athletes and clients are encouraged to pick a repetition range consistent with their goals and to lift a weight which leads to fatigue (only 1-2 good reps left at end of the set) within that repetition range.  '

To learn more on how strength training can improve your health and performance contact your local Physical Therapist.  

Strength Training's Impact on Swim Performance

In the last couple of weeks we have posted on the impact of strength training on endurance performance.  Studies have shown resistance training improves both running and cycling economy leading to faster times.  These studies add to our existing knowledge on the importance of endurance athletes balancing their endurance training with strength exercises.  The pool is no exception with swimmers demonstrating improved sprint times using strength training.  Swimming requires energy contributions from both the aerobic and anaerobic systems and athletes should aim to train their bodies consistent with these demands.  

A recent study examined the impact of 30 second training bouts targeting the major muscle groups involved in swimming.  Belfry and colleagues studies 16 male swimmers and divided them into 3 groups, two training groups and one control group (J Strength Cond Res. 2016).  One training group completed 20 repetitions of strength training exercises within a 30 second time period (consistent with a sprint performance).   The authors tried to exhaust the athlete at the end of the 20 reps, if more could be completed in 30 seconds the weight was increased.  A second training group selected a weight they could lift 80 times in a 2 minute span (similar to a mid distance event) with adjustments made similar to the first group.  Both training groups lifted 3 days a week for 6 weeks.  

The authors reported improved swim times for the 50 and 200 yard distances in the 30 second group, but the 2 minute training group only improved their 200 yard time.  This study adds to the existing literature on the value of strength training for swimmers.  For more information on how strength training can improve your swim performance contact your local Physical Therapist.