Five simple high-intensity workouts
Get more bang for your buck with these five quick and intense workouts. Remember: work smarter, not harder!

Everyone has been talking about the benefits of HIIT; it's a quick workout that burns a tonne of calories.
The keyword being the quick part. An hour of running may burn a lot of calories, but not everyone has an hour to dedicate 4 times a week. Instead, give these workouts a try and let the good times roll (and the calories burn!). Each work out has 5 rounds (except for the full body burn). Rest 30 seconds to 1 min between each set. Let's go!
Legs for days
15 squats x 4 sets
15 lunges x 3 sets
15 side leg lifts x 3 sets
15 fire hydrants x 3 sets each leg
15 plié squat pulses x 3 sets

Arm Lady
15 knee pushups x 3 sets
15 bench tricep dips x 3 sets
15 Supermans x 3 sets
15 inch worm with shoulder taps x 3 sets
15 plank ups x 3 sets

Abs of steel
15 ab crunches x 2 sets
15 twisting crunches x 2 sets
15 air bikes x 3 sets
15 toe taps x 3 sets
1 min plank x 3 sets

Big big booty
30 mountain climbers x 3 sets
30 donkey kicks (15 each leg) x 3 sets
Squat pulses 1 min x 3 sets
30 (weighted) Glute bridges x 4 sets
30 knee to elbow kickbacks x 3 sets

Full body burn
30 squats x 3 sets
30 lunges (15 each leg) x 3 sets
1 min Plié pulses x 3 sets
30 crunches x 3 sets
30 straight leg jackknives x 3 sets
30 mountain climbers x 3 sets
15 burpees x 3 sets
30 glute bridges x 3 sets
15 push-ups x 3 sets
30 tricep dips x 3 sets

Aim to do a combination of these workouts 3 times a week (in combination with a balanced diet) and you should start to see a difference in not only your strength but your lean muscle mass.
Remember: REST IS KEY! Many people think that more is more, but in actuality, less is more! Your body builds and repairs muscle during rest, not during your work out. Overtraining of your muscles can lead to poor performance, muscle deterioration and even injury. So space it out: don't over train and don't train the same group of muscles two days in a row.
Keep it simple and start out with 3 days a week. As you get stronger, you can bump it up for 4 times a week and/or alternate the exercises into harder varieties (e.g. knee pushups --> full pushups).
Happy training!