TURN-ONS AND TURN-OFFS IN CURRENT HOME ENTERTAINMENT RELEASES : VIDEOCASSETTES : Excellent Good Fair Poor

Times writers take a look at a new batch of exercise videos released in time for the ’86 Christmas season. Why do workout/fitness tapes keep on coming? Partly because they sell, and sell big. Beyond that, the growing emphasis on “low-impact aerobics” incorporates alternate and newly developed methods (the “body band” is one of the latest crazes) and takes into consideration safer and more efficient ways of shaping up the old bod. Above all, exercise videos make good sense and--if they’re used properly and regularly--healthier people, destroying the conception that all TV watchers are couch potatoes.

“Jane Fonda’s Low Impact Aerobic Workout.” Karl-Lorimar. $39.95. “Not all exercises are suitable for everyone,” advises Fonda, who is proving to be a genius at exploiting the differences. She has just unwrapped her sixth workout videocassette, which set a record for advance sales (320,000) and signals a new exercise trend: low-impact aerobics. These, explains Fonda, are “gentle to your joints and muscles.” Indeed, the 50-minute routine of warm-up, aerobics and cool-down is lighter than Fonda’s classic workouts, with less jumping around (never do both feet leave the floor at the same time) and a frisky country-music strum replacing the demanding disco beat. Production values are solid and Fonda continues to be an effective, low-key instructor. A nice introduction to home exercise. Information: (714) 474-0355.