Training for Climbing, 2nd: The Definitive Guide to Improving Your Performance (How To Climb Series)

lactic acid can be anywhere from ten to thirty minutes, depending on the initial level of the lactic acid accumulation and whether the rest is active or passive (more on this later).
DEPLETION OF GLYCOGEN
     
    Steady, long-term exercise typically depletes glycogen stores in ninety minutes to two hours. Running out of glycogen causes the infamous hitting-the-wall phenomenon in marathon running, and it is a contributing factor to your inability to climb hard toward the end of a long day on the rock.
    Fortunately, climbing is a stop-and-go activity, so a full two-hour supply of glycogen can be stretched out to last nearly all day. You can also spare your glycogen supplies through regular consumption of additional fuel (sports drinks and foodstuffs) throughout the day. Research implies that carbohydrate feeding during exercise can help extend your glycogen supply by 25 to 50 percent (Coyle 1984).
    Your starting level of glycogen is also a crucial factor in determining how long and hard you will be able to climb. If you are climbing for a second or third straight day, you will certainly have less than the full ninety-minute to two-hour supply of glycogen. This is because complete replenishment of glycogen stores takes twenty-four hours—a good dinner and a full night’s sleep are not enough to restock the supply completely. When climbing on successive days, it’s therefore vital to consume more calories throughout the day (to spare glycogen)—and even so, you will likely hit the wall sooner on day two than you did on day one.
LOW BLOOD GLUCOSE
     
    Blood glucose (sugar) is but one of the possible fuel sources for working muscles, but it’s the only fuel source available to the brain and nervous system. As glycogen supplies dwindle during long-duration activity, the working muscles become increasingly reliant on blood glucose for fuel. As a result, blood glucose levels drop and increasing levels of exhaustion and mental fatigue set in.

     
    Figure 10.1 Recovery Curve
     

    As mentioned above, ingestion of carbohydrates will help delay this fatigue by helping to maintain an adequate level of blood glucose.
MUSCLE CRAMPS AND MICROTRAUMAS
     
    Muscle cramps and microtraumas can contribute to the sense of muscular fatigue, though in somewhat different time frames. Muscle cramps typically occur near the end of an exhausting period of muscle action—for instance, when some of the muscles in your back or arms lock up after a long, strenuous section of jamming or upon reaching complete exhaustion in the midst of a long sport climb. In such an instance, twenty to thirty minutes of rest, gentle stretching, and massage, as well as consuming some fluids, will help alleviate the cramping and restore normal muscular function.
    Microtraumas are a primary cause of the all-too-common delayed-onset muscle soreness (DOMS). This muscle soreness, which becomes evident from twenty-four to forty-eight hours after strenuous exercise, is a result of microscopic muscle tissue tears and the accompanying tightness and swelling (edema). Strength will be diminished for as long as pain persists, possibly as long as two to five days.
CENTRAL FATIGUE
     
    In addition to muscular fatigue, strenuous exercise can have adverse effects on the central nervous system (CNS). This so-called central fatigue can impair coordination, concentration, and your ability to perform difficult motor skills. Repeated high-intensity movements such as lunging and campus training are the hardest on the CNS. However, excessive amounts of any specific training stimulus—fingerboard, Hypergravity Isolation Training, campus training, and such—or performing the same type of bouldering movement over and over can also produce central fatigue.
    Unfortunately, severe central fatigue can take longer to recover from than that due to any of the other causes. Consider that recovery of a nerve cell takes up to seven times longer than a muscle cell (Bompa 1983). Of course, this level of fatigue may never be experienced by the typical recreational climber; whereas elite climbers, who push the envelope both in the gym and on the rock, are likely to experience central fatigue. If you still feel physically “off” even after a few successive rest days, you may be experiencing central fatigue. It may take another two to ten days away from training and climbing to recuperate completely, but you will find yourself performing better than ever after this break away from climbing (per the