It’s the pajama power workout

With days growing short and cool, now’s a great time to stockpile workouts that can be done in the comfort of your home.

So we took the following question to Michael Seril of Whittier, who was recently named personal trainer of the year by the National Strength and Conditioning Assn.: What’s a short, nonjolting workout that does not require you to put shoes on, change out of your pajamas or leave your living room?

He laid out this 20- to -30-minute morning routine for a whole-body strength and light cardio workout. He recommends doing it three days a week.

First comes the warm-up: Walk around the house for a few minutes to get some blood moving. Then it’s one minute of high-stepping, bringing your knees up to waist level. (If people live below you, please do this on a rug.) Then one minute of torsal rotation, twisting side to side (not too severely) with feet planted about shoulder-width apart.

Those of moderate to high fitness should do the following moves with a 5- to 8-pound medicine ball; others can use no weight and still reap benefits.

1.) Power squat: Holding the ball to your chest, squat. Proper technique is abs engaged, back fairly straight (not hunched), feet shoulder width. Sit into the squat until your thighs are parallel to the floor. Make sure knees do not extend beyond toes. Then come back up.

Seril’s version entails raising the ball overhead as you come up, then bringing it back to chest level as you sit into the next squat. “This engages the whole body,” he says, particularly working the gluteus, quads and abs. (Raise your hands overhead if you’re not using a ball.) Do one set of 20. Too hard? Count to 20 by twos.

2.) Back lunge with rotation: Standing and holding the ball to your chest, step straight back about 3 feet with your right foot and rotate your torso to the right. Do 10 reps. Now switch sides, stepping back with your left foot while turning to the left. These work your quads, calf muscles, obliques and glutes. If you find yourself tipping over, shorten the back step.

Return to a squat position, but instead of raising the ball overhead, toss it as you rise up and catch it as you go back down. Do 20 of these.

3.) Side bridge: Lying on your side, prop yourself on your elbow, forearm on floor and perpendicular to your body, then bring your hip up off the floor to achieve a straight line from armpit to ankle, with only elbow and side of foot touching the ground. Hold for 30 seconds on each side. (Rest at 15 seconds if needed.)

4.) Straight-ahead bridge: With chest facing floor and back held straight, prop yourself on forearms and toes, engaging the abs and glutes -- for 30 seconds.