There are gyms, and the world of equipment they bring to a workout. Basements across America contain dumbbells and treadmills, exercise balls and yoga mats and resistance bands.

And there are city parks. Almost all of them have park benches. Denver, Colo., personal trainer Teddi Bryant thinks park benches are ingenious.

"When I go to Washington Park to work out, I'll do a lap around the park and then go and find a park bench," said Bryant, the owner of Hot Mamas Exercise (hotmamasexercise.com).

We asked Bryant to come up with a workout that can be done in a city park. She came up with the park-bench idea. Here, she mixes up exercises between muscle toners and strengtheners, and ones that keep up your heart rate.

Side step-up with kick » Stand beside the front of the park bench, with your left hip beside the bench. Bend your left leg and bring it onto the bench seat. Then, with your hands out at the side for balance, straighten your left leg and lift yourself above the ground. While you are standing on the bench with your left leg, kick your right leg out to the side. Bring the right leg back, then step the right leg back to the ground. Keep the left foot planted on the bench. Repeat 15 times on each side.

Bench fan kicks » Face the side of the bench, standing a few feet away. Kick your right leg across your left leg and raise your right leg above the bench. Then swing it to the right in an arc over the bench. Do it 30 seconds on each side.

Dip with leg extension » Sit on the bench. Place your hands on the bench, on each side of your hips. Keep your feet flat on the ground, with your knees bent. Push into your hands, lifting your butt from the bench seat. Then clench your buttocks and lift your pelvis up. Now, bend your elbows and lower your butt beneath the edge of the seat, all the while clenching your buttocks. Straighten your arms, and while rising, lift one leg up off the ground. Alternate legs as though you are marching in place. Do a set of 15.

Bench kicks » This is basically running in place. Face the bench. Tap one foot against the edge of the seat, then the other foot. Keep alternating feet for 30 seconds.

Push-up with knee-to-elbow lift » Put yourself into the push-up position, with your hands on the edge of the seat of the park bench and your feet straight back. You want to be in plank position -- back straight, abdomen tight. Lower yourself to the bench by bending your elbows, then push yourself back into the starting position. When you are in the plank position, bend one knee and bring it toward your nose, then return to the plank position. Do 15 of these. If your hands are close together, this exercise works your triceps. Farther apart, the more it works your chest.

Lunge with twist » This is a backward lunge, and you stay in place -- you don't walk backward while you are lunging. Place your hands on your hips or behind your head. Bend both knees, and step your right leg behind you. Bend down farther into your knees, for the lunge. While in the lunge, twist your torso to the left. Return your torso to its normal position and stand back up again. Do 15 lunges for each side.

Seated alternating knee to chest » Sit on the edge of the bench and lean back. Lift your feet from the ground and lift your legs up. Pull your right knee to your chest, then return it to beside the left leg. Now pull your left leg to your chest, then return it. Alternate legs like this for one minute, all the while keeping your feet off the ground. You are hovering over the ground.

This is great for your hip flexors, Bryant said. Also, the lower abdominals, the obliques and the spine.

Squat thrusts » Stand up. Bend your knees and squat down. Now, thrust both of your legs out so you are in plank position. Then hop your feet back up toward your hand -- back into the squat position -- and stand up. Do it for a minute.

Plié jumps with assistance » You've seen ballet dancers do the plié -- their feet are cocked to the side, like ducks, and they bend their knees. In this move, stand behind the bench and put both hands on the top of the back of the bench. Cock both of your feet to the side, in the manner of a duck -- the plié. Now squat down, keeping everything straight and above your feet. Maintain good posture. When you reach the bottom of the squat, jump into the air, holding the back of the bench. Land in the plié again. Do this 25 times.

Bench crunch/twist » Lie on the ground, with your feet resting on top of the bench seat, toes pointed into the air. Place your hands behind your head. Now roll up. Try to get your shoulder blades off the ground. Keep your abdomen tight. You want your rib cage knotted into your torso. At the top of the crunch, twist to the left, then to the right, then lie down again. Do it 15 to 25 times.