See SR4A, p. 124, "Physical Active Skills." The ones linked to physical attributes are Climbing, Diving, Escape Artist, Gymnastics, Infiltration, Palming, Parachuting, Running, and Swimming. That's all of the Athletics group, half of the Stealth group, and a bunch of miscellaneous skills.
As for modifiers to split dice pools, see SR4A, p. 150, "Attacker Using a Second Firearm": "Split the pool before applying [dice pool] modifiers." Reflex Recorders are different, though, because they modify your skill rather than the dice pool. See SR4A, p. 61, "A Note on Modifiers" sidebar for a discussion of the difference.