Posts tagged cycling
Older Cyclists Maintain Immune System Function Against Sedentary Peers

Previous research has shown older adults who remain active are able to slow the physiological effects of aging including increased body fat, decreased muscle mass, and muscle weakness.  Other systems in our body also show a decline with aging including the immune system.  Immunesenescence or the decline in immune system function due to aging is an established fact with a decline of 2-3% each year beginning in our 20s.  A new study highlights the benefits of aerobic exercise on immune system function in older adults.

Duggal and colleagues studied 125 active older adults (55-79 years of age) to determine the impact of exercise on immune system function (Aging Cell. 2018).  The authors compared the immune function of these older cyclists to their sedentary peers.  Surprisingly, the older cyclists demonstrated immune functions comparable to 20 and 30 year old individuals.  Specifically, in T cell levels which help the body respond to infections.  The active adults showed less signs of decreased immune system function.  This is the first study to show the positive effects of aerobic exercise on immune system function.

Caffeine's Impact on Recovery After Cycling

Our prior posts have documented some of the research supporting the use of caffeine in both strength training and endurance events.  Caffeine has many effects including increased alertness and decreased perception of pain and fatigue.   These effects on the central nervous system allow an athlete to train harder and longer at a given intensity when caffeinated.  New research is investigating caffeine's impact on recovery from exercise.  

Caldwell and colleagues in the Journal of Strength and Conditioning Research examined the effects of caffeine consumption after a 164 km cycling event.  Each cyclist was randomized to receive either 3mg/kg of body weight of caffeine or a placebo immediately after the ride as well as for the next 4 mornings and afternoons.  Not surprisingly, athletes provided with caffeine reported improved leg function and decreased muscle soreness compared to the placebo group.  The authors concluded cyclists may benefit from ingesting caffeine after endurance events to accelerate recovery.  Athletes are advised to speak with their physician before taking any ergogenic aid.


Prescribed vs. Self Selected Hydration and Cycling Performance

The benefits of proper hydration for human performance and recovery has long been established.  Replacing fluid loss from metabolism, evaporation, and sweating can have a dramatic impact on performance in both team and endurance sports.  As our workouts progress in duration and intensity our requirements for nutrition beyond water alone increase.  Unfortunately, trying to train at a high intensity and drink sufficient fluids can be difficult in many endurance sports.  In fact, prior research shows when athletes are allowed to drink at self selected pace they often become dehydrated up to 3% of their body weight.  

A recent study in the journal Medicine and Science in Sports and Exercise compared a self selected hydration group against a prescribed hydration group as participants performed a cycling trial in the heat (Bardis et al. 2017).  10 elite male cyclists accustomed to riding in the heat performed 3 trials of criterium simulated conditions up to 30km.  The cyclists completed these rides under two conditions, one self selected drinking condition and one requiring them to match fluid losses every km.  The authors found improved performance over the 30 km criterium trial during the prescribed drinking condition secondary to lower dehydration and heat strain, as well as, improved sweating responses.  Specifically, the self selected drinkers had 3 times the amount of dehydration as the prescribed condition.  

Which Disciplines Contribute Most to Triathlon Performance?

Triathlon athletes have varying distances to compete in from shorter sprint races to longer Ironman distance events.  As the events progress from sprint to Olympic to Ironman distance the percentage of time spent in each discipline (swim, bike, run) adjusts with the distance.  Research has shown when comparing the Olympic and Ironman distances athletes will spent a greater percentage of their time running with the longer races while the biking percentage stays relatively stable (Lepers et al. 2013).  Not surprisingly, an athletes time spent during the biking and running sections, due to their duration, has the greatest impact on an athlete's time and performance.   These are often the areas where athletes can have the greatest impact on their overall performance.  

A recent study in the Journal of Strength and Conditioning Research examined the impact of each of the three disciplines on Olympic and Ironman triathlon performance (Figueiredo et al. 2016).  The authors analyzed performances from the top 50 male and female triathlon finishers over a 26 year period.  Within the Olympic distance races the authors noted significant decreases in both swim and run times, but both bike and run times significantly became faster within the Ironman races.  Within the Olympic distance, the run followed by the bike discipline showed the greatest impact on overall performance, but these disciplines had similar contributions to performance in the Ironman event.  

This study indicates the importance of focusing on run performance in the Olympic distance, but Ironman athletes should focus on both the run and bike disciplines to improve their performance.   

Reducing Knee Pain In Cyclists

Cycling is one of the most popular outdoor activities in Boulder.  Cyclists we encounter in our Boulder Physical Therapy practice most commonly complain of pain on the front of their knee or anterior knee pain.  Research shows 1 in 2 competitive cyclists have experienced this knee pain resulting in lost training and competitions in over half of those affected (Clarsen et al. 2010).  A cyclists exposure to the impact of poor pedaling biomechanics is amplified by the volume of their training.  It is not uncommon for a competitive cyclist to flex and extend their knee over 5 million times per year during their training sessions and competitions (Callaghan et al. 2005).  In addition to training errors, bike biomechanics remain one of the key sources of an athlete's knee pain.

Athletes who have excessive movement in their lower bodies both reduce their cycling economy and performance, as well as, increase their injury risk.  In particular, the movement of the knee toward or away from the frame increases stress across the knee especially during the power portion of the pedal cycle.  The suboptimal mechanics change the alignment of the knee and the ability of the leg muscles to import forces on the foot and pedal.  Commonly, bike fitters use shoe orthotics or wedges to modify the relationship between the foot, shoe, and pedal.

Research has shown a rigid cycling shoe is the most economical and efficient interface with the pedal allowing cyclists to pedal at a lower % of their VO2 max for a given work load compared to a softer shoe.   Research regarding orthoses or wedges on cycling alignment and mechanics are fewer in number.  The limited research shows these orthoses or wedges 5-10 degrees can temporarily impact mechanics but their long term efficacy as a tool remains to be limited (Fitzgibbon et al. 2016).  They are most likely to benefit those athletes with true structural alignment impairments in the leg.  

Conversely, many of our patients's symptoms improve quickly with Physical Therapy interventions to correct impairments such as limited range of motion and muscle imbalances in the leg.  Once these are addressed an athlete is better able to use cuing and movement retraining to improve static and dynamic alignment of the knee while cycling.  In summary, athletes need the capacity to control the knee position through strengthening then the appropriate retraining to use that strength in an optimal cycling pedal cadence.  


Strength Training Improves Cycling Performance

As we move towards the end of winter many Boulder cyclists are growing tired of the indoor hours on their bicycles.  One of the benefits of the winter months for cyclists is the opportunity to introduce strength training into their work out programs.  A 2 to 3 day a week, total body strengthening program not only reduces a cyclist's risk for injury, but has recently been shown to improve cycling performance.

As noted in a previous post on running economy, cycling economy is one of three factors shown to influence endurance sports performance.  Essentially how much of a cyclist's energy resources are used to produce a given speed and distance.  At a given speed or power intensity, a less economical or efficient cyclist will ride at a higher intensity of their max, burning more valuable fuel and oxygen, than a more economical or efficient cyclist.  These variations in efficiency are most visible during a cycling competition.

Sunde and colleagues recently examined the impact of an 8 week strengthening program on cycling performance and economy (J Strength Cond Res. 2016).  The cyclists continued their cycling training but also performed high intensity squat training (4 sets x 4 reps) 3 days per week to maximize their positive nervous and muscle system adaptations.  As expected the athletes demonstrated improved strength and power after the 8 weeks, but they also improved their efficiency and aerobic output.  These athletes extended their time to exhaustion at their maximum power output by close to 20%.  

Cyclists are advised to work with a local Physical Therapist to implement an individualized lower body strength training program to improve aerobic performance and reduce injury risk.