I don't think I'm alone in feeling like I get way more pumped ice climbing than rock climbing. How do you beat the pump when you are on ice?
—Dale McElroy | Provo, Utah
It is a popular misconception among rock climbers that ice climbing is easy. With jugs to hang on, how hard can it be? But this is like saying that swimming isn't tiring after doing a few strokes. A pitch may start off feeling easy, but with poor technique the fatigue soon kicks in. On steep ice your forearms will burn from over-gripping and your shoulders and triceps will melt from swinging. Then there is the dreaded calf-pump to contend with. It is crucial to examine the subtleties of good ice-climbing technique before doing more training, otherwise you will simply continue to pour all your fitness down the drain. Examine crampon and axe placements first, then body position and movement skills. But before you start, check that picks, crampon points and screws are razor-sharp, as acuity makes more difference than anything else.
Footwork. Efficient ice climbing begins with your crampons. The kicking angle is crucial. Keep your heels low and resist the urge to press with your toes (this often feels unnatural to rock climbers). Be accurate and look where you're kicking. Aim for steps or lower-angled sections. The secondary points engage when you drop the heel slightly and form a stable tripod. Keep your feet perpendicular to the ice. Monopoints reduce shattering in thin ice and are more accurate. You can also stand in tiny pockets or in your previous pick placements.
Axe work. Use a light, minimal swing. Aim for a secure placement on the first swing, although it is better to swing again than to over-drive. Note that with hard, brittle ice you may need to chip away with several light swings, rather than give it one giant bludgeon, which can destroy the available ice and limit further options. Don't swing just from the wrist or the elbow or shoulder -- you need an equal engagement of all three. Aim high above you, but not for a full stretch. Don't let your elbow drift too far out to the side. Your wrist must flick the tool forward so it accelerates at the final part of the swing, but hold on tightly as the pick engages, both to prevent it from glancing off and to minimize vibration. Be accurate, and if you need to swing again, aim for exactly the same spot unless the placement site was jingus; in that case look for something better rather than hacking the same spot to pieces. Aim for concave features such as pockets, scoops or other people's placements. Avoid convex features such as the front of columns or bulges, as these may shatter. Alter the depth of your placements according to the condition of the ice and safety factors such as the quality of your protection. Ice climbing is not about being a macho hard-hitter, and this approach will pump you out. A skilled ice climber is more of a craftsman and the real pros try to hook with their picks to avoid swinging altogether. The final step is testing axe placements, the key to gaining confidence and reducing physical tension. Simply give your tool a light tug before you commit weight to it, and then relax.
If you get the dreaded jelly arm and your pick glances off with every placement, don't panic. Stop thrashing, shake out, relax and breathe deeply. Don't go for the next placement until you feel a notable recovery, then raise your arm, and with a single confident and accurate swing make your placement. As soon as you have it, relax your grip and shake the other arm. Repeat until you are out of trouble. Another key is to wear flexible, sticky-palmed gloves. Bulky, slick gloves cause you to squeeze harder just to hold on. Proper hand-wear can decrease the pump all by itself.
Body position. On steep ice, keep your arms straight, your legs bent and your center of gravity centralized between your feet. On flat homogenous ice, move with the axes at different heights (rather than level) and roll with the body rather than pulling up and locking off. Staggering your pick placements is an economy of movement that is more efficient and will reduce your fatigue. Moving on complex, heavily featured ice is more like moving on rock, where you look for holds and weaknesses to help you rest and make progress. Maintaining balance on complex ice can also be tricky, so avoid stepping or reaching too wide, and instead keep axes and crampons within shoulder width. Stem wherever possible and don't try to rest unless you are in a comfortable position, which can be devised with most solid placements. Keep your arm straight when resting, breathe deeply, relax your grip as much as possible and keep the weight on your feet. Remember to shake out your feet and calves, too. Finally, it is always better to place gear in rest positions and to avoid placing too many screws on steep sections. The best tactic for steep ground is to keep to a rhythm and to try to climb fast.
You can, of course, do many exercises to improve your fitness for ice, such as roll-ups, wrist curls, shoulder presses and endurance training on plastic, but I don't think that's what you were asking for here. Better to use your brain and save brute force for a last resort.