Ideally, your workout should be quick, fuss-free and well-rounded. In reality, however, most of us play favourites, choosing to do only what we enjoy.

But when you do the same thing day in and out, you're likely to neglect certain muscle groups.

That's why we asked various fitness instructors for these non-negotiable exercises that every woman should do.

RUSSIAN TWIST

Works obliques and abs. Why do it: This toughens up the upper body, and will help in activities that require torso rotation, such as swimming, tennis and golf. How often: Three to five times a week. Sit on mat with knees bent at about 90 degrees. Lean back slightly and clasp hands in front of chest. Contract abdominal muscles. As you exhale, twist torso to left, keeping back straight. Inhale, return to centre and repeat other side to complete rep. Do three sets of 20 reps.

SQUAT

Works quads, hamstrings, inner and outer thighs, glutes and core. Why do it: This exercise recruits many muscles at once, and is incredibly functional. It mimics basic movements like standing up, lifting something heavy off the ground and climbing the stairs. For anyone looking to build a perky butt, squats are one of your best bets. How often: Three or four times a week, with a rest day in between. Stand with feet slightly wider than hips, turned slightly outwards. Pull shoulder blades down and back. Keep chest lifted and chin parallel to ground. Tighten core and abdominal muscles, then shift weight to heels. Push hips back as if you're about to sit on a chair, and lower yourself until thighs are parallel or almost parallel to ground.

Feet should be firm on ground and knees aligned with second toe, without going past toes. Extend forearms in front of you to stabilise. Avoid tucking tailbone or arching lower back. Return to starting position by pushing through heels. Do three to five sets of 10 to 15 reps.

DUMB-BELL PULLOVER

Works chest, back, rear deltoids, triceps and abs. Why do it: Score a stronger upper body for better balance and posture. This move also benefits women at risk of developing muscular imbalance, especially those who tend to carry a child on one side of their hips. How often: Thrice a week, with a rest day in between. Lie face up on mat, knees bent and shoulder-width apart. Hold a medicine ball weighing at least 2kg above chest, arms extended with elbows slightly bent. Inhale and slowly lower ball to back until arms are in line with torso. Exhale and slowly return to the initial position.

Do three sets of 15 reps, resting 20 seconds between each set. If using a dumb-bell, hold it horizontally and grip both ends firmly. Increase weight of medicine ball or dumb-bell as you get stronger.

PLANK

Works abs, obliques and lower back. Why do it: It's a powerful exercise to sculpt and strengthen the core muscles, such as the obliques, abs and lower back. A strong core enables you to perform exercises and daily movements (even sitting down!) with good posture. How often: Twice or thrice a week. In face-down position, balance on knees and elbows with hands balled and wrists facing inwards. Lift body off ground, engaging muscles in back, abs, arms and legs to form a line from head to heel.

Make sure back is not arched and hips do not sag. Keep eyes on hands without lowering head or tucking in chin. Hold for 10 to 15 seconds and repeat three times, resting up to 60 seconds in between. Increase holding time as you get stronger.

BIKRAM HALF MOON

Works abs, butt, hips, thighs, deltoids, trapezius and chest. Why do it: Strike this pose for a more flexible spine, and to alleviate back pain, stiff shoulders and torso as well as scoliosis. It makes you activate the abs, butt and thighs. How often: Every day. Raise arms overhead and interlock fingers. Release index fingers, keeping thumbs crossed. Inhale, then slowly bend body to right and push hips to left until you feel a deep stretch down left side. Keep spine neutral and arms close to ears. Hold for one minute and switch sides. Repeat set once more.

DOWNWARD FACING DOG

Works deltoids, triceps, spine, hamstrings, glutes and calves. Why do it: This common yoga pose strengthens your upper body while giving the spine, hamstrings, glutes and calves a good stretch. Being in the inverted pose boosts blood circulation too. How often: Every day; if not, at least thrice a week. Get on all fours with feet and knees hip-width apart. Place hands shoulder-width apart and spread fingers wide.

Pressing firmly through hands, lift knees off mat and straighten legs. Walk hands forward and feet backwards to adjust position. (If you have tight hamstrings, bend knees gently.)

Squeeze thighs and imagine pressing them against a flat plane. Press heels down onto mat as much as possible. Keep neck relaxed and breathe deeply. Hold for at least 60 seconds.

PUSH-UP

Works chest, triceps, shoulders, upper back and abs. Why do it: The push-up targets the chest, triceps, shoulders and upper back. It activates the core and improves torso stability too, reducing your risk of lower back injuries. How often: Twice or thrice a week, with at least one rest day in between. Get into plank position with arms under shoulders and slightly wider than shoulder-width apart. Body should be aligned from shoulders to ankles. Shift weight to balls of feet. Inhale and lower body until it almost touches mat.

Keep pelvis neutral, elbows close to body, and head in line with back. Exhale, straighten arms and return to the initial position. Do as many reps as you can in proper form. Increase the number as you get stronger.

REVERSE PLANK

Works glutes, hamstrings, abs and back. Why do it: This move isolates and strengthens the glutes and hamstrings, so it's particularly useful for runners. Done correctly, it engages both the abs and back to improve posture. As a weight-bearing exercise, it also helps to build bone density, which is important to fight osteoporosis. How often: Thrice a week. Sit on mat with legs extended before you. Place palms on floor slightly behind and outside hips, fingers spread wide. Pressing into palms, lift hips and torso towards ceiling, until body is aligned from head to heels. Look up slightly and point toes. Keep arms and legs straight. Hold for 30 seconds and repeat three times, resting up to 60 seconds in between.

• This article first appeared in Shape