Tuesday, August 3, 2010

Strength Training for endurance paddlers

We often equate endurance athletes such as long distance paddlers and runners to aerobic animals; those animals that rely heavily on oxygen delivery and use in the muscle over very prolonged periods of time. Compared to the Olympic weightlifter, there is nothing explosive about an endurance sport. Thus, it follows that endurance athletes will train to enhance their ability to delivery and use oxygen and avoid muscle hypertrophy and explosive strength training. An endurance paddler or runner can spend over 20 hours a week paddling or running as part of his or her training regimen. That doesn’t leave much time for supplemental training or pursuing another type of activity to combine with the primary one.

While devoting the majority of training specifically to their sport, an endurance athlete might add an endurance weight training program (such as circuit training) to compliment their activity. But, is it possible that the endurance athlete is missing out on something by not lifting heavy weights with the goal of increasing neuromuscular strength and power? A research group in Finland tested the effects of 3 different types of strength training on endurance performance in runners. Several recreational male runners who were taking part in a marathon training school were recruited. The group was divided into three types of weight training programs; maximal strength training, explosive strength training and circuit weight training. The circuit trained group was the control group and used only body weight as a form of resistance (such as squats, lunges, push ups and sit ups). Following 9 sessions of weight training prep, each group engaged in their respective weight training program for 8 weeks. Maximal strength training consisted of heavy load resistance while the explosive training consisted of power lifts and squat jumps. The runners continued their running program while strength training.

They measured several performance variables related to distance performance including aerobic capacity (VO2max), running velocity at VO2max and running economy

What they found:

  • Circuit training did not increase VO2max, velocity at VO2max or running economy
  • Neither maximal or explosive strength training increased VO2max
  • Both maximal and explosive strength training increased velocity at VO2max and running economy
  • Both maximal and explosive strength training increased muscle activation and strength

What does this mean to the endurance athlete? Since the beginning of time, endurance performance has been attributed to the cardiopulmonary system’s ability to delivery oxygen to the muscle and the muscle’s ability to use that oxygen. Typically, this is assessed by measuring VO2max. Traditionally, very little of endurance performance has been attributed to neuromuscular function, until lately. The neuromuscular adaptations that come about through maximal or explosive strength training (that which requires maximal recruitment of muscles) do seem to play a significant role in endurance performance. More recently, the running velocity sustained at VO2max has been given consideration as a true endurance performance predictor. Another good predictor is running economy, which simply means the ability to run at a faster pace for a given amount of energy expended. There is evidence that neuromuscular adaptations contribute to both of these predictors of performance.

Bottomline: as an endurance athlete, it may be to your benefit to strength train your muscles. It will not increase your aerobic capacity, but it might improve your paddling speed and that’s what it’s about in the end. As paddlers, you use your torso and leg muscles significantly. Because your arm and shoulder muscles are smaller, it might be safer to begin a strength training program by focusing on your lower body first. Before engaging in upper body strength training, first work those smaller support muscles in your shoulder. For instance, internal and external rotation movements with a thera-band or pulley are excellent exercises to strengthen those rotator cuff muscles and help you avoid injury. After some training of the smaller muscles, continue with larger multi-joint lifts such as bench press, lat pulldown, shoulder press or seated row.

Taipale, et al. Strength training in Endurance Runners. Int J Sports Med, 30: 468, 2010

Friday, June 4, 2010

When nature calls

Imagine the scene where you have been exercising hard in the heat for a long period and have not taken the time to drink fluids, not unusual for a kayaker. You’ve been sweating and your body is dehydrated. You finally take the time to drink some water. To quench your thirst, you finish off an entire water bottle within seconds. Feeling refreshed, you continue paddling. Within minutes, you get the annoying urge to urinate.

To rehydrate, it is in the athlete’s best interest to replace 100% of fluids lost. The amount of ingested fluid that is retained (not converted to urine) reflects the efficiency of rehydration. Thus, the athlete would want 100% efficiency. So what affects efficiency? A recent study by E. J. Jones and colleagues from Stephen F. Austin State University and the University of Alabama tested the effects of a large amount of water intake vs smaller amounts taken intermittently over a period of time on rehydration efficiency.

In their study, 8 healthy men walked on a treadmill in an environmental temperature of 95ºF (35ºC) until they achieved a 2% loss of body weight. For a 170 lb person, 2% is equivalent to 3.4 lb or 1.6 liters of water. Following the exercise, participants were given a light breakfast and 4 hrs later were fed lunch. Each participant performed this protocol twice; one time given a large amount of water during breakfast equivalent to the amount lost during exercise (1.6 liters) and another time the same quantity of water given in 8 smaller doses over a 4-hr period (0.2 liters every 30 min). Urine was collected and measured over an 8-hr period following exercise. Hydration efficiency was determined as the (fluid lost - urine produced/fluid lost x 100).

What they found

  • Urine production following one dose of water equivalent to amount lost was .70 liters vs .42 liters when same amount of water was given in 8 smaller doses over 4 hrs
  • Hydration efficiency (the actual amount ingested that stayed in the body) was 55% following one dose of water equivalent to amount lost vs 75% when same amount was given in smaller doses
  • Within the 8-hr period, about 2/3 of the urine produced occurred during the first 4 hr regardless of the method of water consumption

What this means

Aside from the results of this study, it has been previously shown that in order to 100% rehydrate with water, 150% of what was lost must be consumed. One explanation for this is that the kidneys are over stimulated in an attempt to maintain normal blood osmolality (electrolyte concentrations) and volume. This is because water consumption reduces blood osmolality quickly. The response is a decreased secretion of the anti-diuretic hormone which leads to increased urine production. What is also known is that rehydration efficiency is higher when fluids containing electrolytes and carbohydrate (i.e. Gatorade) are consumed. Unlike plain water, sport drinks do not cause a rapid decline in blood osmolality, and thus, result in less urine production.

The bottomline

The overstimulation of kidneys can be more effectively avoided when water is consumed in smaller amounts over a period of time rather than consumed as a large amount at once. However, you will produce urine no matter what and you will need to consume additional water to compensate for this loss if you want to completely rehydrate. Drink fluids frequently during exercise and following exercise. Of course, if you are exercising and sweating for a period of time, you’ll need to replace carbohydrates and electrolytes, in addition to water. Most sport drinks do a good job replacing all three. Try to consume all three essentials during exercise as well as following exercise.

Reference: Jones et al, Effects of metered versus bolus water consumption on urine production and rehydration. Int. J. Sport Nutr Exerc Metab, 20, 2010.

Wednesday, April 21, 2010

Ibuprofen topical gel for muscle pain: does it work?

Non-steroidal anti-inflammatory drugs (NSAID) are commonly used by athletes for various reasons such as muscle soreness from a particularly intense workout, exercise-induced headaches, joint or muscle pain during exercise, and musculoskeletal injury pain. However, some individuals cannot use the oral version of NSAID because of GI distress or adverse effects when taken in combination with other drugs or for other reasons. Thus, topical analgesics may be an effective alternative for athletes experiencing muscle or joint pain. There have been several studies attempting to test topical NSAID effects on muscle soreness following muscle-damaging exercise. While positive results have been reported in some, others have not shown benefits.

A recent study continues this discussion by testing the efficacy of Ibuprofen topical gel in both men and women who engaged in unaccustomed gym exercise. They recruited a large population (65 women, 41 men) ranging in age from 18 to 65 yr because they were interested in comparing men and women, and young and old. The gel consisted of a 10% Ibuprofen concentration. A visual analog scale was used to assess muscle soreness (see below) on the back of the thigh and on the upper arm.

Testing was randomized and everyone performed the test twice with a 3-wk period in between. Some participants received the placebo during the first test and the ibuprofen during the second test and the others received these in reverse order. The exercises were performed with one leg and one arm and the left and right sides were also randomized for testing. The exercise performed included the preacher curl and knee flexion exercises. Everyone performed 6 sets of 10 reps at 80% 1RM (1 repetition maximum), and 3-min rest between sets. Sets were performed to failure.

Pain was assessed beginning 36 hr following exercise and every hour for 6 hours thereafter.
During the assessment, a lift was performed at full ROM for each exercise. The weight lifted was very little, 1 lb for arm and 5 to 10 lb for leg. After the first pain assessment at 36 hr, a topical gel was administered. The treatment amount applied to the skin was equivalent to 125 mg of ibuprofen and the placebo gel contained no ibuprofen.

What they found:
  • level of pain was highest at the 36 hr time, gradually decreasing during the 6-hr period
  • no difference in pain between ibuprofen and placebo
  • no difference in pain between men and women
  • older adults experienced a higher level of pain regardless of the topical gel

This study was very well designed. The tests and treatments were randomized and they used a “cross over design” (everyone was tested with the ibuprofen and the placebo) with a long period in between treatments. They tested a very well screened population, they had a large number of participants and these individuals were all relatively unaccustomed to exercise. If they had used athletes for this study, the results may have been different. For instance, thletes might perceive pain differently than non-athletes because they are more accustomed to it.

What does this mean for you? Once again, this is one of those things where it might help you, but it more likely will not. But, never underestimate the power of a placebo; simply rubbing gel on your sore muscles may actually reduce your pain. For instance, I apply Tiger Balm to my sore muscles on occasion and I swear that it does help and I’m sure many others who use it feel the same. The topical Ibuprofen might be worth trying, especially if you do not wish to take ibuprofen orally. Also keep in mind that some pain may be an indication of overuse injury. In which case, anti-inflammatory drugs may be necessary along with other forms of treatment.

One last word, the FDA recently sent a letter to several manufacturer’s of topical ibuprofen and warned them that their product must be removed since it has not received FDA approval. Here’s the link to that:


Hyldahl et al, Effects of Ibuprofen topical gel on muscle soreness. Med Sci Sports Exerc 42: 614-621,2010.

Tuesday, March 16, 2010

Exercise in the heat: does precooling help?

Well known to athletes are the negative effects of heat on performance during prolonged exercise. It there is a way to reduce these effects, an athlete should be interested in trying it out. One strategy is pre-cooling and several studies have found a positive effect from it. Precooling methods have included ice vests, cold towels, cold water spray, cold showers or immersions, and cold rooms; and the longer and larger the cooling stimulus, the greater the improvements in performance. How these methods affect exercise performance appear to be associated with reduced cardiovascular strain, improvements in oxygen supply, and reduction in the accumulation of anaerobic metabolic byproducts, chemicals that can increase muscular fatigue.

A recent study in Medicine and Science in Sports and Exercise attempted to test the benefits of precooling on self-paced endurance performance in male cyclists. This type of protocol allows the athlete to determine his or her own pace with the intention of completing a specific distance or amount of time. In other words, it simulates a race, but does so in a controlled lab environment. Two randomly-ordered 40-min time trials were completed on separate days in a 91º (50% humidity) environment. On one of those days, athletes immersed their lower body to hip level in 57º water (sounds painful to me!) for 20 min prior to the time trial.

What they found

Precooling resulted in the following:

  • increased power output during the 40-min time trial, especially during the final 10 min of the ride, resulting in a greater estimated distance covered (19.3 km vs 18.0 km)
  • lower skin and core (rectal) temperatures during the first 15 min of the time trial
  • no change in heart rate or rating of perceived exertion, but a lower thermal sensation

What does this mean for you? Physiologically, precooling had no profound effects except for a lower body temperature which would be expected. Cardiovascular response was not changed, nor was the muscle’s ability to contract. However, performance was improved and isn't that what it's all about? Although the improvement was not huge, any amount will benefit the athlete and even a small improvement can make the difference between first and second place.

How does one precool? When I lived in Tucson, I would soak my cotton t-shirt in cold water before putting it on just before a run. It really helped keep me cool, despite the fact that it would be completely dry within 15 minutes of dry desert air exposure. For a kayaker, it may be as simple as water immersion prior to paddling. The athletes in this study were immersed up to their hips. The authors didn’t mention whether or not they were wearing shorts. I suspect not. If the direct benefits are dependent on which muscle groups are immersed, than it makes sense that a kayaker will want to immerse his or her upper body. In which case, wet clothing may be the downside of doing this. Regardless, if precooling is possible before exercising in the heat and you can do it without too much discomfort (i.e., wet clothes), go for it. It can’t hurt you, unless you give yourself frostbite from rubbing ice cubes on your skin.

Reference: Duffield et al, Med Sci Sports Exerc. 42, 2010

Friday, September 25, 2009

Recovery from long distance: how about a bowl of cereal?

Over the past couple of decades, much work has come out of the Exercise Physiology and Metabolism Lab at the University of Texas at Austin. Much of this work has demonstrated the positive effects of combining protein and carbohydrate intake both during and following a long bout of exercise (a few hours, give or take). The merits of carbohydrate have been well known by athletes and scientists alike but its only been recently that the significant contributions of dietary protein for endurance performance and recovery have been investigated in well controlled studies.

The group at UT Austin has a new study out in the Journal of the International Society of Sports Nutrition (Kammer et al). They attempted to make this investigation more practical to athletes by testing the effects of eating a bowl of cereal with nonfat milk against a popular carbohydrate sport drink. Twelve cyclists and triathletes (8 men and 4 women) performed two 2-hr bouts of cycling at a moderately high intensity on separate days. Following the ride, they were provided either 40 oz of sport drink containing 78.5 grams of carbohydrate or a bowl of whole grain cereal and 1/3 liter of nonfat milk containing 59 grams of carbohydrate and 7.3 grams of protein. They were also give 3/4 liter of water on the cereal day to match the fluid amount of the sport drink.

The investigators measured muscle glycogen levels (biopsy needle method) immediately following exercise and again 1 hr later. They also measured blood glucose, insulin and lactate levels. Muscle tissue was also analyzed for proteins that are involved with glycogen and protein resynthesis through the effects of insulin.

What they found:
  • Insulin levels were higher during the 60-min recovery period during the cereal trial compare to the carbohydrate drink trial.
  • Glucose levels were similar between trials during the 1-hr recovery.
  • Glycogen resynthesis was similar between trials during the 1-hr recovery.
  • Muscle tissue proteins were similar between trials during the 1-hr recovery.

What does this mean for you? If you prefer cereal and milk following a long workout or race, go ahead and eat as long as you rehydrate as well. Cereal and milk are just as effective for glycogen replenishment as a sport drink. Another way to look at this is that the protein from the cereal and milk provides no additional benefits to glycogen resynthesis as long as the amount of carbohydrates is adequate. Practically speaking, it comes down to personal preference once again. As long as you consume adequate carbohydrate and protein following a long bout of exercise, you'll do just fine regardless of the source.

The recommended amount of carbohydrate or carbohydrate + protein following a glycogen depleting bout of exercise is 1.2 grams for every kilogram of body weight per hour. For a 150 lb person, that's about 80 grams of carbohydrate or 55 grams of carbohydrate + 25 grams of protein. For a 180 lb person, thats about 100 grams of carbohydrate or 65 grams carbohydrate + 35 grams protein.

For more information on protein-enhanced supplements go to my website: http://cmierphotoandfitness.net/protein.html

Reference: Kammer et al. Cereal and nonfat milk support muscle recovery following exercise. J. Inter. Soc. Sports Nutrition, 2009.

Friday, July 17, 2009

Energy balance during multi-day backpacking

Doing field research is tough. Those extraneous variables (like the environment or exercise intensity) that scientists love to control often make interpretation of results difficult. And many times, the logistics make certain measurements impossible. Imagine trying to get a blood or urine sample from a long distance paddler during a 300-mile race. It's a catch-22 for field studies. You want to take the athlete out of the lab and place her in the environment in which she is use to training and competing. The results will have more meaning, at least to the athlete. On the other hand, you want your measurements to be scientifically meaningful and this is very difficult when they are not performed under controlled conditions. So when reputable scientists seek to study athletes under real-world situations, I have to hand it to them. A recent study with backpackers fits the bill.

Hill and colleagues studied 3 experienced backpackers during a 5-day hike on the Appalachian Trail in Virginia. The hike totaled 161.5 km (100 miles), ranging from aboutr 18 to 23 miles each day. Elevation ranged from about 660 feet to just over 4400 feet. Temperatures ranged from 46 to 72 degrees fahrenheit, not reaching over 57 degrees on most days. The three hikers were a 32-yr old female, a 34-yr old male and a 52-yr old male.

Prior to the hike, each hikers was tested in the lab to determine VO2max and to determine the relationship between heart rate and VO2 during under various walking speeds and grades and with pack weight added. A graded test was performed beginning at a speed of 3 mph and increased to 4 mph at 20% grade. Heart rate and VO2 were measured during each stage.

During the hike, a heart rate monitor was worn at all times. During rest stops lasting more than 1 minute, the hiker recorded the average heart rate response during the previous hiking interval. Resting energy expenditure was estimated based on body weight and net energy expenditure (what was spent during activity) was estimated from the heart rate response. Energy intake was measured.

On average, the hikers walked at speeds ranging from 2.1 to 2.8 mph, the fastest average speed occurring on days 1 and the lowest on days 2 and 5.

What they found:
  • Average heart rate was 105 bpm
  • Hikers spent almost 100% of their hiking time in light to moderate level activity
  • Total daily energy expenditure approached 5000 calories on days 1 to 4
  • Total daily energy intake averaged just over 2100 calories
  • Expected weight loss was 1.8 kg (4 lb) and actual average weight loss was 1.7 kg
  • Rate of calorie expenditure during hiking was 6.3 cal/min, ranging from 2.1 to 15.6
What can long distance paddlers take home from these data? For obvious reasons, backpackers limit their food intake based on pack weight and will almost always experience negative energy balance during multi-day hikes. This may be comparable to a paddler who limits his or her intake because of constant paddling and the inconvenience of accessing food. On the other hand, these hikers hiked for up to 8 hours a day and no more. They also hiked at relatively light to moderate intensities. No doubt, a paddler engaged in a multi-day race such as the Everglades Challenge will be expending energy at a much higher rate (at least twice as high) and continuously for a much longer period than these backpackers and thus, will experience a more dramatic negative energy balance.

Five days is not very long to determine how well the body adjusts to chronic negative energy balance and how a backpacker adjusts his or her mileage and hiking speed over the long haul. This is a good introductory study into possibly a longer study that would involve hikers during an Appalachain Trail through hike. Likewise, I would like to see studies that test paddlers under similar conditions when they are training or competing. There is much to be learned out there from paddlers who experience the real world day in and day out.

Reference: Hill et all. Energy balance during backpacking. Int. J. Sports Med. 29, 2008.

Monday, July 13, 2009

Ingesting sport drinks during exercise: does this interfer with training adaptations?

Endurance exercise training has profound effects on the structural and functional characteristics of skeletal muscle. Scientists refer to muscle's remarkable abilities to adapt to chronic exercise as plasticity. Muscle plasticity is evident by two important outcomes from endurance training, improved endurance performance and increased use of fat. The muscle's ability to use more fat is beneficial to prolonged exercise performance because it slows the rate at which muscle glycogen (a finite source or energy) is used, thus allowing the athlete more power output before fatigue. Among the specific adaptations in the muscle that allow greater use of fat are increased fatty acid transporters located in the muscle cell membrane and increased enzymes that promote fat oxidation.

We know what happens to muscle with training, but what isn't yet totally clear is how these changes are initiated. Current evidence suggests that with every bout of exercise, changes in gene expression are taking place. In this particular scenario, this means an increase in protein expression for certain proteins such as fat transporters and oxidative enzymes. Exercise provokes changes in messenger RNA which in turn increases the muscle cell's ability to produce proteins that are needed for exercise. Why an increase in fat transporters? Perhaps it is a survivial mechanism. Exercise heightens the energy state of the muscle cell, which means more energy sources and oxygen are required. From a survival point of view, if you are going to submit your muscles to this demand, the muscle will have to adapt in order to sustain such activity over and over again. It makes sense from a Darwinian perspective.

Consider the question, "What if you keep feeding the muscles glucose during exercise and by doing so suppress the use of fat?" When glucose is ingested, the muscle will prefer glucose over fat. This results in improved performance because the muscle, 1) can produce more power from glucose over fat, and 2) it's being provided another source of glucose and thus, blood glucose levels are more easily maintained. But, what if glucose ingestion during each bout of exercise interfers with gene expression that favors fat oxidation? Will this stunt muscle adaptations that ultimately lead to improved performance?

In steps Thorbjorn and colleagues from the University of Copenhagen, Denmark. They hypothesized that glucose ingestion during exercise would alter the gene expression of fatty acid transporters and enzymes. There results are published in the July 2009 issue of the Journal of Applied Physiology. To test their hypothesis, they asked 9 men to participant in a unique 10-week training program. To make each participant his own control, training consisted of 1-legged cycling. One leg was assigned the glucose trials and one leg was assigned the placebo trials. They trained one leg at a time on alternate days, 5 days per week. This meant each leg received on average 2.5 training sessions per week. They were given a 6% glucose solution (such as Gatorade) at a rate of 0.7 g/kg/hr during the glucose training sessions. Each participant performed a fatiguing test and performance was measured as length of time. The investigators also measured fat metabolism.

What they found:
  • Training improved maximal power and time to fatigue, no difference between glucose and placebo
  • Training increased fat oxidation during exercise, no difference between glucose and placebo

The investigator's hypothesis that glucose ingestion during training exercise would alter fat adaptations that normally occur with training was not supported by these results. Noteworthy is that training sessions did not differ between glucose and placebo, meaning each leg received the same training stimuli. This is good to know because it is possible that not ingesting glucose under certain circumstances would reduce training power output, thus reducing the training stimulus. Theoretically, because of this, not ingesting glucose could negatively affect training adaptations. But because there was no difference between trials in terms of training stimulus, this confounding effect seems to not be an issue here.

Bottomline: Keep drinking your Gatorade, your muscles will adapt just as well. And for athletes who train several hours daily, not consuming glucose during exercise will likely have a greater negative impact. Despite carbohydrate ingestion, athlete's muscles are trained to use more fat, which is one reason for their awesome endurance.

Reference: Thorbjorn et al. Glucose ingestion during endurance training does not alter adaptation. J. appl. Physiol. 106, 2009.