Most rock climbers know the feeling: the quivering muscles and tentative moves of the first routes of the season. But Eliza Rayner said her climbing ability is at its peak in early spring.
"By August, I'm weak again. It's really sad but true," said the Boulder, Colo., science teacher, who has been climbing for 10 years.
What gives? Rayner climbs indoors at the Boulder Rock Club, The Spot, Rock'n & Jam'n, and the Paradise Rock Gym during the winter, building strength, stamina and confidence in a controlled environment. When the weather warms enough to head outdoors, she's ready.
"If you ski, you can only ski a portion of the year," said Kevin Smith, owner of the Thrillseekers climbing gym in Denver. "When you come back, your skills will have diminished."
Not so with climbing. Athletes can take advantage of facilities indoors.
The steep overhanging routes typical of indoor climbing gyms require more strength than what Rayner tackles outside, and staying on what climbers call "the sharp end of the rope" -- lead climbing -- gives her the mental ability to pick up each spring where she left off in the summer.
Indoor climbing facilities range from walls in retail shops to 12,000-square-foot gyms dedicated entirely to climbing.
Indoor climbing walls usually consist of a faux-rock surface with strategically placed "holds." Holds are made from colorful, synthetic materials to mimic the shapes and textures one might find on real rock. In a gym, the holds are rearranged every few weeks to keep the routes fresh.
Bryan Mallin, co-owner of the Paradise Rock Gym in Denver, said there is a certain skill to arranging the holds -- called "route setting" -- to provide a quality experience for climbers of different levels.
"There is high-quality route setting. It's great as a Front Range climber," Mallin said.
The methods of climbing also re-create the outdoor experience. Climbers can choose to lead a climb, which means they are tied into a rope, which they clip into protective gear throughout the route.
Taking a "lead fall" means dropping two times the distance from the last point of protection. Climbing with the awareness that one slip could mean a 20-foot free fall requires confidence and mental focus.
Most beginning climbers start out by top-roping -- they are attached to a rope that is suspended from above. If they come off the wall, they will drop only slightly as the elasticity of the rope gives to their body weight.
The third alternative of indoor climbing is bouldering, or working on lateral routes closer to the ground, without ropes and harnesses.
While some climbers, such as Rayner, have the dedication to climb inside all winter, others flock to the gym with the first hints of warm weather.
"March is always busy because people who don't climb a lot in the winter are thinking about spring and summer and come in to get in there," said Matt O'Connor, co-owner of the Boulder Rock Club.
"A lot of people take a break in the winter and go skiing. In March, you are thinking about climbing. You want to build endurance, build some power back up, get back into the swing of things and get some more confidence."