Hydration and Carbohydrate Replacement
Cross Country Training
While distance runners should be concerned about fluid replacement every day that they are in training, the summer heat puts these concerns at the top of the list. Like so many issues in sport training there is no shortage of anecdotal information about hydration, and then there is the scientific research. The goal is to effectively replace the fluid that is lost due to sweating and respiratory loss that occurred during the workout that day to aid in a speedy recovery. A simple answer of how much to drink would be to way the athlete before the run, and then after. The lost weight is water and needs to be replaced. Because water is such a good solvent, the thought is that while the water is being replaced perhaps other water soluble nutrients such as carbohydrates (CHO) and electrolytes should ride along with the water into the body. There has been some research that shows adding protein to a carbohydrate rich drink may speed the absorption of the fluid and carbohydrate by the body. How about the timing of consuming the water or carbohydrate drink to enhance recovery? Research done at the Boston Marathon over the past eight year’s shows that a surprisingly high number of runners finished the race with too much water in their system. These runners over-drank during the race which caused their sweat to be too dilute, causing it to drastically lose its effectiveness.
Most of the fluid that a normal person loses each day is replaced via the foods we eat. Distance runners need to replace a greater quantity of liquid and drink more. They may drink water, a sport drink, or a natural carbohydrate drink such as orange juice or milk to replace lost fluid. They may also drink carbonated soda or energy drinks; however, neither of these is effective in replacing fluid and do add the burden of other issues as well. They will not be addressed here and their use should be discouraged.
Our bodies desire stability of homeostatic issues. Stable metabolic temperature, water and food supply, and oxygen concentration are less stressful to the body then those that wildly fluctuate. When I go to across country meet I see some athlete’s drinking water before the race while others are sipping off of a sport drink. Which drink is better before the race, after the race, or is it just personal preference?
Figure 1. indicates blood work from two distance runners (Hulston et al. MSSE. 2009). The data points on the graph indicate the carbohydrate concentrations in the blood before and during work done at the aerobic threshold. The difference in the two lines is drastic and shows the carbohydrate dissolved in the blood and available for muscular fuel between someone who drank a sport drink before the work and someone who only drank water before the work. The work starts at time = 0. One hour before the commencement of work, one athlete drank only water, while the other drank only a sport drink. When the work started the carbohydrate drinker had a lot more fuel available in the blood, but after 15 minutes of aerobic threshold running the fuel supply in the blood had collapsed. The water drinker actually increased the available fuel in the blood in a more systematic way. The bottom line is that if you are an 800 meter runner or a miler, it probably makes no difference in how you pre-race hydrate, but anything longer as a race or workout, there will be issues. Sport drinks appear to be most effective post-workout as a means for re-hydration and replenishment of some lost carbohydrate. However, as the evidence shows, within one hour of longer races water should be the main means of hydration.
Some recent studies have indicated that ingesting small amounts of protein in a carbohydrate sports drink may aid in performance. It probably does not aid in the actual performance during the activity and should not be ingested during the run, but taking in this type of drink post-workout would be effective. A more natural alternative to protein rich sports drink could be chocolate milk of all things. It contains the natural proteins found in milk with the additional carbohydrate to chocolate it up. Research has shown this chocolate drink closely matches the nutrition of sports drink.
Cross Country Training
- Keeping the body core cool needs to be addressed. The best means for achieving this is to slow the pace down: in other words lower the metabolism. Do not go for a fast run on a very hot day.
- Make sure conduction is at maximum. The best means for achieving this is to make sure the blood volume is at maximum levels. Keep the hydration high. Go on long runs on very hot days only when you have the aerobic adaptations to do that.
- Maximize the body’s convection possibilities. Wear loose fitting clothes on hot and humid days, or no shirt at all. Wear modern quick-drying fabrics, and do not wear cotton. Shade the face with a modern fabric cap.
- Keep evaporation occurring on the body’s surface areas. The human body is nearly 70% water, and even a small water loss has drastic effects and will cause blood and sweat volume level problems as a first response. In addition, the most effective sweat has an electrolyte composition to it that must be maintained during heat stress.
- Heat cramps: sodium and potassium loss and dehydration. Treat by hydrating with water and feeding with electrolyte drinks.
- Heat exhaustion: body core temperature hovering near 103 degrees. The treatment is stopping the activity, moving to the shade, elevating the feet and hydrating. Seek medical aid.
- Heat stroke: core temperature at 105 degrees and climbing. The treatment is the same as heat exhaustion, with the addition of packing in ice. Seek medical help immediately.
- Make a note to discuss with your team the importance of hydration and the need for electrolytes before and after practice on all days, but especially the days with a higher heat index.
- Keep a list of treatments in your running or coaching log in case you have to react quickly to heat stress in your runners.
- Study the concept of acclimation. Understand the time periods involved as your runners try to travel and compete in more tropical weather conditions than they are used to.
Dissecting Elite-Level Workouts
Training theory is a fascinating point of discussion for most middle-distance coaches. These conversations can vary from something as simple as typical microcycle mileage to something as detailed as workout construction. There is no doubt that there are “many roads to Rome” in the journey to getting a talented middle-distance runner into top physical condition. There are a large number of variables that go into such a project, but success usually boils down to appropriate workout stimulus and sequencing workouts in a logical manner that follows basic biological principles of adaptation.
Middle-distance workouts can be simple or complex. It is not necessarily the design, but the level of stimulus that is most important. The most basic work that is done in middle-distance training is on the aerobic side. There is no need to make continuous runs anything more than what they are. The duration of the run serves as the main variable to consider when constructing a workout, although intensity becomes a key factor in a tempo run. The real creativity in work is usually found on the anaerobic side of development. That is, the training area of race pace and faster. The theme for any workout is to do the least amount of work to achieve the desired stimulus.
Consider a single round of anaerobic repetitions, or the same repetitions broken up into multiple sets; which is the best road to take for success? The most skilled middle-distance runners benefit from complex anaerobic workouts, while beginners do fine with a simple design. However, skilled or beginner, there is no doubt that multiple sets of work allow an athlete to do more volume and/or intensity then single sets of repetitions do. It then becomes the art of training design to construct the proper workout types for your athletes.
Let’s take a detailed look at four different, high anaerobic percentage workouts, designed for elite athletes. Note the style of the work and the volume/intensity of the stimulus. These are advanced workouts for skilled athletes, but the principles of training remain the same no matter what the skill level of the athlete is.
1) The athlete is a 1:51 800 meter/4:06 mile athlete in the Specific Preparation Period. A ladder workout. The prescribed work is: 1600meter – 1200 meter – 800 meter – 400 meter at approximately 4:33 per mile pace. The rest/recovery interval would be 2000 meters of volume between each repetition of work at 5:20 per mile pace. Total volume of the workout is 6 miles. A ladder can be done in one of two ways: the pace stays the same as the work distance changes, or the pace changes as the work distance changes. The described workout would consist of work components of the former design. This type of ladder works well in advanced, elite runners, that are addressing development of the combined anaerobic and aerobic energy systems that are fairly close to race pace.
2). The athlete is a 1:51 800 meter/4:06 miler in the Specific Competition Period. This is a sets and repetition workout designed to build capacity. The prescribed work is: two sets of three repetitions of 300 meters at 40 seconds which is near race pace. The rest/recovery is 1600 meters at 5:45 pace between the repetitions and an additional three minutes of light jogging between the two sets. The total volume of the workout is eight miles. This sort of workout is designed as a lactate tolerance workout done correctly at race pace.
3). Elite middle-distance runners can also benefit from sophisticated ladder workouts that get progressively faster as the work distance decreases. These workouts are generally known as single breakdowns. The athlete is a 1:51 800 meter/4:06 miler in the Pre-Competitive Period. The prescribed work is a five mile breakdown at 3k pace. The components are 1 x mile @4:24, 2 x 800 meters @ 2:11, 4 x 400 meters @65 seconds and 8 x 200 meters @ 31 seconds. The rest is a 400 meter jog between each of the 15 bouts of work. Total volume for the workout is eight miles. This sort of workout takes a very long time complete, and is athlete and date specific. This is not a workout to do in a diverse training group, but rather in a very small homogenous group.
4). The last middle-distance workout to dissect is the double breakdown style where the athlete alternates in breaking down two different racing distances within the same workout. The athlete is a 1:51 800 meter/4:06 miler in the latter segment of the Competitive Period. The components of the workout are a set of 4 x 400 meters alternating between 3k goal pace and 1500 meter goal pace, followed by a set of 4 x 300 meters alternating between 3k goal pace and 1500 meter goal pace. The rest between each 400 meter bout of work is a 400 meter jog and between each 300 meter repetition is a 500 jog. Between the two sets is an active three minutes of additional jog recovery. Like the other three workouts described, the overall goals of this workout is physiological race modeling and lactate tolerance.
Use creativity in setting up sophisticated anaerobic work in the combined zone. Understand what the outcome is expected to be from these workouts. Like any work done such as these sessions, adjust the rest interval so the athlete can complete the high-level work
Cross Country Training
Understanding and following proper nutritional protocol is crucial to the success of any athlete. Human cells require nutrients ingested from outside of the body to provide an energy platform for muscle contractions, amino acids for synthesizing a wide variety of protein-based components, and micro-nutrients that provide a sort of co-enzyme function in many cellular functions.
Eating is a very personal human activity. The role of the high school cross country coach is to provide the athlete with a basic understanding of scientific principles regarding nutrition, not to plan and dictate every meal and snack for the team members. Perhaps the most important concept to be taught is the role of carbohydrates in a cross country runner’s diet. Armed with that information a runner can make sensible choices about diet selection and gain an understanding about the timing of carbohydrate ingestion before their races.
Think of carbohydrates as the body’s jet fuel supply. Carbohydrates are the preferred energy-rich molecules for striated muscle contraction and the only fuel source the brain can operate with. For that reason, storage of carbohydrate is essential in the body. Carbohydrate is stored in the three separate ways: Muscle and liver glycogen and blood glucose. Consuming adequate carbohydrate on a daily basis is necessary to replenish both types of glycogen between daily training sessions and competitive events.
Stored muscle glycogen dwarfs the glycogen amount stored in the liver, but both sources are important in the training regime of the cross country runner. For example, a 12 mile long run for a runner (training at 60 miles per week) will come close to exhausting both supplies of glycogen if done too fast. Glucose saturated in the blood only contains enough energy to run one mile, so it needs to be restocked by glycogen stores continuously while running longer distance.
The energy demands of running dictate that carbohydrate is the preferred fuel for exercise intensities above the aerobic threshold. Lipid oxidation cannot supply ATP fast enough to support such high-intensity running, although it contributes a fraction of the amount needed. Lipids supply more calories per gram of substrate than carbohydrate, 9 KCAL/gram compared to 4 KCAL/gram but the process of oxidation of lipids is much slower.
There is a statistically significant correlation between the pre-exercise muscle glycogen stores and the length of time running can be performed at 75% of VO2 max. The more embedded the quantity of muscle glycogen, then the further one can run.
Studies have shown that a mixed diet of 50%/50% carbohydrate produced a muscle glycogen content of 106 mmoL/kg wet muscle weight and enabled the subjects to run for 115 minutes at 75% VO2 max before the glycogen supply was compromised. A low carbohydrate diet (less than 10% of KCAL from carbohydrates) produced a muscle glycogen content of 38 mmoL/kg and supported one hour of running at the same intensity. However, a high carbohydrate diet (more than 80% KCAL from carbohydrate) provided 204mmoL/kg of muscle glycogen and enabled the subjects to exercise for 170 minutes at the same intensity.
Liver (hepatic) glycogen stores are also important for distance runners. Hepatic glycogen stores can be emptied by a 15 hour fast of carbohydrate. One study showed a drop from 490 mmoL/kg on a 50/50 mixed diet to 60 mmoL/kg on a low carbohydrate diet. A high carbohydrate diet can increase liver glycogen content to about 900 mmoL/kg.
A high carbohydrate intake acutely enhances a cross country runner’s recovery and improves endurance performance over 24 to 72 hours. One study reported that a high carbohydrate diet (80% KCAL carbohydrate or 8.8 gm/kg/day) restored endurance capacity within 22.5 hours of recovery between training sessions. Cross country runners in season should consume 7 to 12 gm/kg/day of carbohydrate. For a 140 pound distance runner (62 kg) that converts to about 620 grams of carbohydrate per day. That would be the equivalent of two foot-long veggie submarine sandwiches per day.
The Glycemic Index (GI) provides a scientific way to rank carbohydrate rich foods according to the blood glucose response following intake. Generally foods are divided into those with a high GI (glucose, bread, potatoes, breakfast cereals, sport drinks), a moderate GI (sucrose, soft drinks, oats, tropical fruits [bananas]), or a low GI (fructose, milk, yogurt, lentils, pasta, nuts, non-tropical fruits [apples, oranges]). GI tables are readily available on the internet.
Some research suggests that manipulating the GI of snacks and meals may enhance carbohydrate availability and improve athletic performance. For example, low GI carbohydrates may be recommended four to six hours before exercise to promote sustained substrate availability. Moderate GI carbohydrates may be recommended during breaks between events at track meets to promote rapid carbohydrate oxidation and after exercise to promote glycogen repletion. High GI carbohydrates should be consumed during the two to four hour window following a cross country meet to enhance long term glycogen repletion.
It should be emphasized to your athletes that the total amount of carbohydrate consumed is the most important consideration for replenishing glycogen stores following daily training sessions and competitive events like time-trials and races. In the current era of diet books that run the range of recommended carbohydrate intake it should also be emphasized that any runner on a low-carbohydrate diet is asking for chronic exhaustion and decreased performance.
Dealing with Common Running Injuries
All middle-distance athletes desire a pain-free road to the top. Unfortunately, that scenario is very unlikely, as humans do not have it in their genome to either run far or fast without structural breakdown. With this in mind, a track coach should be well-versed in two aspects of the team members’ musculo-skeletal health: common running injuries that are likely to occur and causes of these injuries. It should be made clear from the outset that a coach is not a physician, and while it is fine to voice a diagnostic opinion based on coaching experience, it is not acceptable for a coach to evaluate moderate to serious musculo-skeletal injuries and prescribe therapeutic treatment.
A list of common running injuries would include problems with the skin and toenails, connective tissue manifestations of the ligaments and tendons, stress fractures of the bones of the foot or leg, striated muscle contraction limitations, bone growth plate irregularities, and plantar fascitis.
Skin and toenail problems can usually be handled by the athlete with assistance from the school athletic trainer. Blisters are usually treated by cleaning it with alcohol and puncturing with a sterile needle. A light coating of Neosporin and a compression bandage should then be applied. A subungual hematoma is a blood blister under the toenail caused by poorly sized shoes. Many times these are not painful and should just be left alone. The nail will eventually fall off. If it is painful, then an athletic trainer will need to drill a small hole to relieve the pressure. Fungus toenails are very common with distance runners due to constant micro-trauma to the nail plate. Fungal toenails are rarely painful and do not cause problems to the foot. A serious long distance runner seldom has ten healthy toenails and even if treated with oral medications the fungus returns.
There are many tendons in the leg and foot as they connect muscle to bone. The most common tendon injury is to the Achilles tendon. The other two common problems are shin splints, which is tendon related, and inflammation to the posterior tibial tendon. The term tendonitis refers to pain and inflammation of a tendon. The treatment for tendon injuries include: relative rest/cross training, physical therapy, oral medications, and orthotics. More aggressive treatment involves stimulation with ultra-sound. Shin splints are a very common running injury. The term medial tibial stress syndrome (TSS) is a better name since it is a combination of bone and tendon that causes the manifestations. TSS presents with diffuse but sometimes localized pain along the medial tibia. Swelling is limited. Fasciculations or ridges may be felt in chronic cases of TSS. Treatment involves strengthening the posterior muscle, physical therapy, proper shoes, arch supports or orthotics and limited use of over the counter pain medications.
Statistics show the most common season ending injury for high school and collegiate runners is a stress fracture. Treatment for a stress fracture depends on the bone and the diagnostic used to identify the fracture. Most stress fractures are not detected in x-rays but are seen in most MRI images. There are five metatarsals in the forefoot and this is a problem area. Most often the stress fracture is in the middle set of metatarsals. Diagnosis of a metatarsal stress fracture is easy. There is localized pain and swelling on the top of the foot. Pain increases with palpation. X-rays may be negative up to one month from onset of pain. Tibial stress fractures are also negative on x-rays at first but do show up after four weeks. These fractures are more prevalent than commonly thought. They may suddenly appear after one session of hard work, and this is in contrast with fractures of the foot that seem to get progressively worse. Treatment involves 2-3 weeks in a boot and running should not resume for 5-6 weeks. The pain is acute and localized and seldom radiates to the medial side.
Plantar fascitis is one of the most common injuries found in runners, but it is not too prevalent in high school or collegiate middle-distance runners. The injury is chronic inflammation of the fasci fat pad under the heel and could lead to a bone spur. Padding in the shoe generally helps the problem. 24 hour treatment is required for this stubborn injury. When an athlete gets out of bed in the morning sandals should be worn. Barefoot walking on hard surfaces is strictly forbidden at any time. Rolling around a golf ball with the bottom of your foot while seated has had positive effects.
Growth plate injuries are common in boys as young high school runners. Osgood-Schlater and Sever’s disease are the two most common problems. With Osgood-Schlaters disease the tibial tuberosty has not yet fused with the tibia. With Sever’s disease, the back of the calcaneous has not yet fused with the heel bone. Pain usually occurs around the time of a growth spurt. The bone grows a little faster than the muscle and the muscle pulls on the growth plate causing pain. Treatment depends on the degree of pain and appearance of swelling. Unfortunately, anywhere from a lessoning of running to a period of time in a cast may be necessary. Stretching when the area is not swollen is helpful, as are shoe modifications and taping of the area.
Many running injuries of the leg can be traced to inflexibility in the pelvis and hip of the athlete. Prior to the year 2000, most running injuries were thought to be related to problems in the foot that manifested themselves in upper leg injuries. It was the bottom-up theory. Now most running injury diagnosis seems to follow the top-down theory that points to the pelvis and hip as the root of most leg injuries. A well thought out and habitually done stretching protocol of the muscles of the hip and pelvis is a great injury prevention routine. Muscles located in the pelvis and butt are among the largest muscles of the body and are neglected by most athletes because they are so durable.
Please remember that every athlete is different and manifestations are unique to the individual. When you do encounter problems, ice is almost always safe to use on any overuse type injury. Oral medications such as ibuprofen should be used with caution. Studies have shown that high school students are showing early stomach ulcerations due to overuse of non-steroidal anti-inflammatory medications.