Exercises not to do

• Don't do tricep kickbacks, do skull crushers

• Avoid because... "Anytime a gym user performs a kickback they look like a drunk guy trying to start a lawnmower on a boat," says McTeggart. "The body twists and squirms, the arms flail about all over the shop and the triceps cry out for stimulation, as every other muscle takes the brunt of the weight." It's not a good look. And it's not a good exercise. Avoid.
  
  Do instead... Decline dumb-bell skull crushers
  
  Why? The decline dumb-bell skull crusher puts all the emphasis on the triceps. Unlike the kickbacks' high postural demands, it takes the body out and puts the triceps in. "With less nervous system demands the arms receive all the love and not just a kiss on the cheek," says McTeggart. Score!
  
  Form Take two light dumb-bells and lie back flat on a decline bench with your arms outstretched above you. With palms facing each other, bend at the elbow and lower the weights towards your shoulders. Your arms should remain parallel as you extend the arms back up to the start position.
  
  Progression To fill your sleeves try working on a 4/0/1/0 tempo recommends McTeggart: "Lower the weight to the count of four and without a pause return to the start position. Don't rest at the top and work again into a four second eccentric lowering phase." You can mix things up further by switching between barbells and dumb-bells and varying the bench incline.

• Don't do crunches, do Swiss ball planks

• Avoid because... "The rectus abdominis – commonly known as your six pack – does not function primarily to bend the torso, but rather to brace the spine and transfer power from the hips to the upper torso," explains personal trainer Chris Bathke. What's more, he adds, a recent article by one of the foremost researchers on core and back health, Dr Stuart McGill, outlined how our lumbar discs can only take so many repetitions of flexion (such as a crunch) before injury and pain occur. Cap'n Crunch is a breakfast cereal. Not an aspirational nickname.
  
  Do instead... Swiss ball planks
  
  Why? They work the core the way nature intended – with little to no strain on your back. And they work it hard.
  
  Form Assume a plank position with your elbows on a Swiss ball and feet on the ground. Tighten your glutes and brace your core as if about to get punched. Now push your elbows against the Swiss ball while maintaining a stable torso. Three sets of 30 seconds should suffice.
  
  Progression Take the same position on the ball but this time move your elbows in a circular pattern (like this chap). Again, make sure there is as little movement in your torso as possible. Do 15 seconds one way then switch directions for two or three sets.

• Don't do leg extensions, do squats

• Avoid because... "Leg extensions can grind the knee joint and put connective tissues into compromised positions," says personal trainer Scott H. Mendelson (completegymsnutrition.com). "The isolated nature of the movement can shut off the proper activation of certain muscles while placing excessive stress on muscles meant to be used in conjunction with prime movers."
  
  Do instead... box squats
  
  Why? "Squats recruit more leg musculature and help it to fire appropriately under realistic conditions that an athlete or weekend warrior may face," says Mendelson. "The coordination skills necessary for proper muscle firing are crucial for protecting the knee against injury."
  
  Form Stand with a chair or box placed directly behind you. Place the bar on the upper back – not the neck. Hold the bar with a firm grip at a comfortable hand width. Retract the shoulder blades while at all times looking straight ahead, eyes fixed on a specific point of reference. As you initiate the squat, push your backside out and lower yourself onto the chair or box as if you were going to sit on it. Once you've made contact, pause, then explode upwards back to the starting position. "The backward movement will help to recruit the glutes and place stress on the knees," explains Mendelson. The core must be kept tight throughout the movement to support the load on the spine. Aim to descend over four to five seconds.
  
  Watch this video to see an example. Over-zealous grunting optional.
  
  Tip "Performing the squat without a bar with the hands folded behind the head is a good way to learn the movement – while a weighted vest can provide loading without over-stressing a novice trainee," says Mendelson.

• Don't do upright rows, do bar-bell hang clean & presses

• Avoid because... "Upright rows are one of the most widely recognised exercise moves you will see on the gym floor," says MH Online Fitness Editor Neil McTeggart. "Aimed at targeting the shoulders and upper back, they can cause shoulder problems for many trainees." Neck and biceps tendon pain are also a risk if the move is repeatedly executed with poor form.
  
  Do instead... bar-bell hang clean & presses
  
  Why? They provide the same stimulation as upright rows with far less risk of injury or muscle pain.
  
  Form Take a bar-bell and hold it with your arms hanging down by your side. Pull up with the elbow and catch under the bar at shoulder height. Then, press the bar overhead while maintaining perfect posture. Lower the bar to the chest and control back down to the starting position. Here's an example.
  
  Tip For further stimulation, McTeggart recommends adding in an overhead shrug: "Once you pull the bar and press above the head keep your arms locked out. Then, without bending your arms, depress and elevate the shoulders, keeping the bar vertical and your back straight at all times." Add 5 of these in at the top of each rep to shred your shoulders even faster.