“Conditioning for climbing is as different from other sports’ training programs as vertical departs from horizontal,” Eric J. Hörst aptly writes in his new Conditioning for Climbers: The Complete Exercise Guide ($19.95, globepequot.com). This manual fills that gap with surefire strategies for honing not just physical fitness (power, endurance, and balance), but mental and technical skills, as well. Throughout, Hörst hammers the point that variety is the key to maximizing results — otherwise you risk plateau, injury, or (worst of all) boredom.