Rehydration
Unless training is very light or water losses via sweating are negligible, a third restoration technique—rehydration—is also an essential part of the recovery process. Runners can lose up to 2 liters of body water per hour during strenuous effort, and losses in body fluids can amount to over 3 percent of body mass in certain situations; performance can suffer when depletion exceeds just 1 percent of mass. Ingestion of fluids during workouts and races generally cannot keep pace with the amount of fluid lost via sweating. Research suggests that it is advantageous to reverse fluid deficits as quickly as possible following workouts and competitions.
Bottled water has become very popular with runners, but pure water is not the drink of choice for such reversals unless it is combined with electrolyte-rich foods. The problem is simply that pure water, when taken by itself during the immediate recovery from strenuous exertion, lowers blood plasma osmolality and plasma sodium concentrations. As a result, thirst is reduced, and urine output increases—the exact opposites of the effects desired for optimal rehydration.12
Instead, fruit juices and sports drinks with electrolytes are preferred for quick rehydration. Bear in mind that satiation of thirst is a poor indicator of the restoration of body water, and thus it is important to continue drinking electrolyte-containing drinks in a reasonable way even after the sensation of thirst disappears. If travel is undertaken during the period between workouts or just before an important competition, remember that the dry air in airplanes increases respiratory evaporative water loss; athletes have been found to have reduced urine volumes after long flights, a sign of dehydration.13 During air travel carried out before competitions or during periods of strenuous training, drinking electrolyte-rich beverages during the flight(s) would appear to be optimal.
When workouts or competitions are carried out in a dehydrated state, running capacity is impaired. Cardiac output is depressed because of the decrease in blood volume, and thus O2max falls. If significant dehydration is present, body temperature may rise too quickly during running, and studies suggest that dehydration may lead to a loss of motor control, which would harm running economy.14 Runners should drink electrolyte-rich beverages after workouts and then consume enough fluids of all types between training sessions so that urinary output is light yellow in appearance; dark urine suggests dehydration, while colorless urine can be an indicator of overhydration.
Downhill Running
In addition to a cool-down, deep-water running, and rehydrating properly, carrying out a session of downhill running on a regular basis can also boost recovery. This is indeed surprising since downhill running has often been linked with muscle damage and soreness. The link between downslope exertion and gradually improved recovery is an example of the repeated-sessions effect in which an activity that initially produces pain tends to produce increasingly less discomfort and trouble when repeated over time. This phenomenon was described by M.J. Cleak and R.G. Eston of the Wolverhampton School of Physiotherapy and the University of Liverpool in 1992.15 Cleak and Eston noted that strenuous or unfamiliar training often produces delayed-onset muscle soreness (DOMS) and that the appearance of DOMS is associated with prolonged recovery times. Therefore, they reasoned, anything that thwarts DOMS should speed recovery time and lead to more consistent and more productive training.
Downhill running provides significant protection against muscle soreness, especially in the quadriceps muscles.
Wayde Carroll/Accent Alaska.com
Cleak and Eston also noticed that DOMS is most likely to occur as a result of repeated eccentric contractions during which muscles are stretched out while they are simultaneously exerting force and attempting to contract.16 In contrast, isometric and concentric contractions, even when completed with high force loads, seem to produce significantly less DOMS.17 Most runners know this already. Any runner who has carried out a training session that involved a significantly unusual amount of downhill running can testify to the pain eccentric contractions can leave behind.
Downhill running can put the quadriceps muscles and hip adductor sinews under enormous eccentric strain. The quads attempt to control flexion of the knee under high-impact loads as the body falls farther with each step downhill. The adductors try to restrain abduction of the femur under intense accelerative forces created by the extra downward falling. The DOMS that results in the quads and adductors can amplify the need for recovery and force the postponement of high-quality workouts.
However, actions that involve high eccentric loads, while they may initially produce significant DOMS and a recovery time that is significantly longer than usual, also have a protective effect that makes it much harder for muscle soreness to develop after subsequent challenging training sessions: the repeated-session effect.
This effect was noticed in a study completed by J.A. Schwane and R.B. Armstrong in 1983 that found downhill running caused muscle damage but then prevented muscle injury during subsequent sessions of downhill exertion; uphill running did not have a similar, protective effect because uphill work could not block the damage correlated with downhill effort.18 The protection provided by downhill running against soreness induced by subsequent downhill, level, or uphill training has been documented in a number of follow-up investigations. Protection from soreness and underlying muscle damage gained via an occasional session of downhill running is an important recovery-enhancing technique: It reduces the recovery time required between quality workouts and thus promotes more frequent and higher-quality training.
Unfortunately, the amount of downhill running required to produce an effective DOMS shield and thus faster recovery is not known. In the laboratory, as few as 12 strong eccentric contractions have been linked with a protective effect against DOMS, a barrier to soreness that lasts for about 2 weeks.19 However, it is very doubtful that 12 downhill running steps would produce a similarly tough barrier against running-linked DOMS. An intriguing study found that two 12-minute sessions of downhill running on a 10 percent gradient provided protection against DOMS in a subsequent downhill run completed 3 days later.20 Unfortunately, this investigation was not continued over a longer period.
There is even debate about how long the protection lasts, with some experts indicating 2 weeks and others suggesting that the obstruction of significant DOMS may persist for 10 weeks or more after a major eccentric challenge. It is reasonable to think that a hill session that involves at least 15 total minutes of downhill running conducted every 3 weeks or so will provide good protection against DOMS and thus decrease the amount of time required for recovery after high-quality or prolonged workouts.
Naturally, it makes little sense to bound downhill for a total of 15 minutes if one’s training has featured very little downhill work in the past. If this is the case, an athlete might profitably start with just 3 minutes of downhill running and progress in 3-minute increments every week or so until the 15-minute goal is reached. Of course, unless a runner lives at the top of a mountain or canyon, completing 15 minutes of downhill running means that he or she will have to be able to finish off more than 15 minutes of uphill running prior to the downhill surge. It is nice to note that such upslope training will be great for running-specific strength, running economy, lactate-threshold speed, and vO2max.
Doubts About Some Recovery Techniques
Little evidence exists that several putative recovery techniques actually enhance recovery. Pharmacological recovery techniques, with the use of nonsteroidal antiinflammatory drugs, have generally been found to be ineffective.21 The same can be said for ice massage22 and contrast bathing (i.e., alternating cold and warm water around the legs).23
Endorsed by marathon world-record holder Paula Radcliffe, cold-water immersion (i.e., placing the legs in a tub of ice water) is a popular recovery technique among competitive endurance runners and is widely believe to minimize inflammation and soreness. However, cold-water immersion, also called cold therapy, ice bathing, and cryotherapy, has not fared well in scientific res
earch.24 One study carried out by Australian researchers suggested that cold-water immersion could actually “do more harm than good.”25 In this inquiry, ice-bath therapy actually increased soreness on the day after an intense workout and had no positive impact on swelling, strength, performance, or blood concentrations of chemicals that are linked with muscle damage. Other research suggested that ice baths should not be used during training because they tend to retard the “growth and strengthening of muscle fibers.”26
Sleep
There is one recovery technique that is unquestionably beneficial, however, even though it is probably the restorative strategy that is most often overlooked. Good-quality, adequate sleep can speed recovery and boost running performances while poor sleep can lead to subpar times. In a study carried out at the Centre for Sport and Exercise Sciences at John Moores University in Liverpool, eight physically fit males who normally slept about 8 hours per night were abruptly restricted to 3 hours of sleep for 3 consecutive nights.27 Workouts were conducted between 17:00 and 19:00 in the evening.
Before and during the sleep-deprivation period, the subjects conducted training sessions that included four weight-lifting movements: biceps curls, bench presses, leg presses, and dead lifts. For each of the exercises, the subjects began with 20 reps at about 40 percent of the one-repetition maximum, followed by a maximal lift. For the maximal effort, the load handled on the baseline day before sleep deprivation was used to begin the test. This load was then increased or decreased in a progressive fashion to determine the heaviest weight that could be lifted.
The results indicated that sleep loss hurt both submaximal and maximal performances. One night of restricted sleep had a minor impact on both kinds of performance; 2 nights of bad sleep were required before submaximal and maximal strength were truly impaired. Such findings suggest that runners should not worry about a night of bad sleep. Significant downturns in performance do not appear to occur until 2 nights of limited sleep have been experienced, with things getting even worse after 3 nights of insomnia.
Since sleep can have a major impact on performance, a sleep schedule should be planned as carefully as the workout. It is important to set a regular time to go to sleep—and stick to it—and to avoid disruptions of sleep, avoid taking the problems of the day to bed, and enjoy each night of sleep. The best endurance runners in the world—the elite Kenyans—are usually in bed and fast asleep each night by 9:30 p.m. and ordinarily sleep until at least 6:00 a.m.28
Nutrition
Proper nutrition also enhances recovery. For runners, high-carbohydrate diets optimize muscle glycogen levels, and higher muscle glycogen concentrations improve endurance-exercise performance.29 Achieving high glycogen levels is not just a matter of eating plenty of carbs, however; the timing of carbohydrate intake is important. For example, consumption of carbohydrate immediately after either endurance or resistance exercise may enhance total daily muscle glycogen resynthesis compared with consuming the same amount of carbs earlier in the day or postponing carb consumption until a few hours after exercise.30, 31 Chapter 44 discusses nutrition for endurance and speed in greater depth.
Taking in carbohydrate right after an exertion does more than boost muscle glycogen creation: It also seems to have a pronounced effect on protein metabolism. Proteins are the building blocks of muscles, and certain proteins can also serve as energy-releasing enzymes within muscle cells. For example, postworkout carb consumption can decrease the rate of protein degradation in muscles32 and increase whole-body protein synthesis.33 These twin effects are highly desirable for endurance athletes, whose performances will generally fall if significant quantities of protein are lost.
When day-to-day training is strenuous, or when training increases in volume or intensity, considerations related to total carbohydrate intake, the timing of that intake, and the impacts of diet and training load on protein metabolism become particularly crucial aspects of recovery. Upswings in training can deplete muscle glycogen stores and throw runners into a state of negative nitrogen balance, in which they are losing more protein than they are making.
Research strongly suggests that endurance runners should ingest 4 grams of carbohydrate per pound of body weight per day during periods of strenuous training, including 1 gram of carbohydrate per pound of body weight immediately after a workout ends. This postworkout carbohydrate intake should be accompanied by 10 to 20 grams of protein (see chapter 44 for more details).
Conclusion
Overall, the importance of recovery should not be underestimated; runners should never forget that the benefits of great training can be canceled quite easily by poor recovery practices. After strenuous workouts, it is good to cool down with about 5 minutes of easy running and 5 or more minutes of stretching. Remember that prolonged cool-downs may hurt muscle glycogen levels during periods of challenging training. Rehydration is a key component of recovery; runners should try to ensure that their urine retains its ideal pale-straw coloration during periods of challenging training. Carbohydrate and protein intakes should be optimized between training sessions.
Deep-water running is also an excellent recovery strategy on the first day or so following a rugged running session. During deep-water running, it is even possible to crank up the intensity without inducing additional muscle soreness or stiffness—and probably without setting back the ability to conduct subsequent, high-quality running sessions on land. Downhill workouts minimize the risk of recovery-retarding DOMS, and occasional blips in the quality of sleep should be followed by solid nights of slumber.
The elite Kenyan runners may be the absolute best in the world at recovering between workouts, with their reliance on minimal cool-downs, substantial sleep, rehydration (with colossal cups of Kenyan tea), postworkout carb and protein intakes, and repeated sessions of downhill running (sadly, no deep-water running is involved . . . the crocodiles, you know). Runners can use these same strategies to optimize their own recoveries and thus move their training intensity and overall fitness up several notches. The end result should be improved performances in key competitions.
Chapter 22
Periodization and Block Systems
Runners who want to improve their performances cannot train in the same way all the time. Training that remains fixed at a specific volume and intensity produces adaptations that cannot advance above a certain level. For example, running 35 miles (56 km) per week throughout the year, or over the course of many years, with a speed session each Tuesday, a tempo run each Thursday, and a long run during the weekend, can push O2max and vO2max up to specific heights beyond which no further improvements are possible without a productive change in the overall training plan.
Figuring out how to modify training in order to keep improving key physiological variables is thus a primary goal of serious runners. The human body’s strong tendency to merely maintain physiological status quo in association with a certain level of training, even when that training is challenging and is continued indefinitely, is an inescapable fact. Nonetheless, many runners train in the same fashion nearly year round, year after year. In spite of their inability or unwillingness to change training in a productive way, such runners expect dramatically improved competitive results over time.
An individual runner’s ability to improve his or her performances will depend on success in upgrading the seven key performance variables:
vO2max
tlimvO2max (i.e., the length of time a runner can actually sustain vO2max; tlimvO2max varies from 4 minutes to a maximum of about 10 minutes, and performance capacity improves as a runner moves up this scale over time)
Running economy
Lactate-threshold velocity
Resistance to fatigue (i.e., the ability to sustain desired goal speed over the full distance of one’s competitive event)
Running-specific strength
Maximal running speed (i.e., power)
When each of these variables is pushed during training to its maximal limit, a runner’s trainin
g has been optimized, and the best possible performances will be achieved.
Exercise scientists believe that no single workout can simultaneously improve all seven variables. A long run, for example, might be good for upgrading resistance to fatigue at the pace chosen for the long run, but it would have no positive impact on maximal running speed because of the submaximal pace, and it would have little effect on lactate-threshold velocity because the training tempo is below threshold speed. Similarly, a hill workout might thrust oxygen-consumption rate and blood lactate upward, thus possibly benefiting O2max, vO2max, and lactate-threshold velocity, and the hills would definitely enhance running-specific strength and therefore running economy, but the slower pace used on hills compared with intense running on the flat would be unlikely to provide a major boost for maximal running speed.
No single workout can serve as a fitness magic bullet; therefore, workouts must progress in difficulty over time to continue challenging the body, and workouts need to be changed over time in order to optimize all seven variables. Finding the most productive workouts—and scheduling them in an optimal way—is one of the key challenges of endurance training.
Improving Through Progression
The strategy of changing training in order to make it more physiologically and competitively productive is called progression or progressing. The most guileless and popular pattern of progressing with training is to increase weekly mileage; two other popular techniques are increasing the intensity and the frequency of training. The problem with these techniques is that they are strategies that merely hope for the best: A runner may move from 30 to 40 miles (48-64 km) per week and hope for good results, for example, without knowing exactly how he or she will change physiologically in response to the increase in volume.
Running Science Page 30