4-Week Bikini-Body Workout Plan

Banish winter fat and get bikini-ready with this hard-HIITing four-week cardio and training plan.

Not so long ago, “getting ready for summer” meant one thing — total boredom. In other words, those monotonous, long-winded 40- to 60-minute cardio sessions plodding along on a treadmill or pedaling away on a stationary bike to nowhere, in the hopes of eventually burning enough calories to squeeze into your warm-weather wardrobe.

Thankfully, science has found a better way. It’s called high-intensity interval training and is essentially a method to incinerate more body fat in a shorter period of time. Combined with another innovative HIIT technique called Tabata intervals, you’ll have a one-two punch to transform your body in as little as four weeks

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Scientifically Shredded

In order to burn as much body fat as possible, you need to perform workouts with a high metabolic cost — intense exercise that stimulates all the major muscle groups. These kinds of workouts mobilize lipase, an enzyme that releases fatty acids from adipose tissue (that would be your muffin top). These acids move into the bloodstream and then to the mitochondria to be burned for energy.

HIIT is by far the best way to boost workout density — the total amount of work you can cram into a certain time frame — and incite this catalytic chemistry needed to burn fat. With this cardio style, you alternate short periods of near-maximal intensity output with a recovery-level pace in a repeating pattern. As a simple example, if you were outdoors running, you could do a 20-second sprint followed by a 40-second jog, or a 20:40 interval. The active phase can be shorter or longer based on your personal fitness level, and the rest period should be as long as necessary for you to be able to give 100 percent effort on the next sprint. A novice athlete may want to start with 10 seconds of harder activity coupled with 50 seconds at the slower pace and work toward a more intermediate and advanced level of 30:30 or even 60:60, always keeping in mind you shouldn’t lock yourself into a rest period that’s too short for you to fully recover.

Research has shown again and again that HIIT burns fat and spares muscle. One oft-cited overview of research compiled in the Journal of Obesity concluded that regular bouts of HIIT produce significant increases in aerobic and anaerobic fitness while also lowering insulin resistance and inciting a number of muscle adaptations that result in enhanced fat oxidation and improved glucose tolerance. Other research has focused on HIIT’s ability to reduce subcutaneous and abdominal fat.

The Summer Strong-and-Shred Program

In a typical training schedule, you’d likely perform one or two HIIT sessions per week, leaving at least 48 hours in between those bouts to recover. For the purpose of this plan, you’re going to push it a little, crafting a four-week overreaching program, which forces your metabolism to adapt to higher demands.

Each week, you’ll consolidate your strength-training workouts into three days of full-body training and will add in three HIIT workouts and one Tabata session. Whether you follow our sample workout week or build your own schedule, just know that when a HIIT or Tabata session falls on the same day as weights, do the weights first so you can be at your strongest for lifting. Schedule one to two days of complete rest for optimal recovery (drop a full-body weight-training day if your recovery is lagging), and always perform some mobility and flexibility activities before and after your workouts.

One thing to note: This is an overreaching program and is designed to optimize fat loss while maintaining and building muscle. However, because of its intensity, return to your normal schedule after four weeks — six weeks max — to prevent injury and overtraining.

HIIT Workouts

These three HIIT programs use a variety of equipment, including a rower and a treadmill, and were designed by Erin Stern, two-time Figure Olympia champion, Oxygen Challenge coach, Dymatize athlete and author of The Bodybuilder’s Kitchen: 100 Muscle-Building, Fat-Burning Recipes, With Meal Plans to Chisel Your Physique (Alpha, 2018).

HIIT A: Bike Blast

Adjust an Airdyne or Assault bike to fit your frame and warm up with three to five minutes of moderate cycling. Then perform the sprints as directed, counting the calories burned versus a specific time period per sprint. Afterward, cool down similarly with three to five minutes of slow pedaling.

The Workout

Week 1: Do 10 sprints of 10 calories each at 90 percent intensity.

Rest at least 60 seconds between sprints.

Week 2: Do six sprints of 30 calories each at 80 percent intensity.

Rest at least 90 seconds between sprints.

Week 3: Do eight sprints of 20 calories each at 90 percent intensity.

Rest at least 75 seconds between sprints.

Week 4: Do eight sprints of 25 calories each at 100 percent intensity.

Rest at least 75 seconds between sprints.

HIIT B: Treadmill Hill Sprints

This plan starts with five minutes at an easy walking or jogging pace with the treadmill set a 3 to 5 percent incline to warm up and prep for the upcoming sprints. Next, set the incline to 10 percent and choose a speed halfway between your warm-up and sprint pace. “A good one is usually between 7 and 8 miles per hour,” Stern suggests. “Stride for 30 seconds at that pace. If you’re really winded after that, you’re very close to your sprint pace. If the stride was easy, increase the speed.” Here’s a four-week program starting at a 7-mph pace:

The Workout

Week 1: Do six 20-second sprints at 10 percent incline and a speed of 7 mph.

Week 2: Do six 20-second sprints at 10 percent incline and a speed of 8 mph.

Week 3: Do six 20-second sprints at 10 percent incline and a speed of 9 mph.

Week 4: Do six 20-second sprints at 10 percent incline and a speed of 10 mph.

Instructions

“Start each sprint with the treadmill set to a 10 percent incline at a 3- to 4-miles-per-hour walking pace,” Stern explains. “Increase the belt speed to your sprint pace and perform the sprint. At the 20-second mark, grab the rails and step off onto the sides of the treadmill before adjusting the controls back down to 3 to 4 miles per hour. Walk for three to four minutes before the next sprint.” As for rest, take as long as you need to be able to go all-out during the next sprint. To cool down, walk 10 minutes and finish with full-body stretching.

HIIT C: Rower Ladder

To begin, warm up with five minutes of easy rowing. “Focus on getting loose and gradually elevating your heart rate,” Stern says. Next, set the rower damper to 5 and row at a 50 percent effort for 30 to 50 seconds. “Keep an eye on your strokes per minute, as this will help you gauge where you need to be for the full sprints,” she instructs. “If you’re very winded, you’re very close to your sprint pace, but if the effort was easy, increase your strokes per minute during the workout.” Here’s a four-week program starting at a damper level of 6 and nudging that up by one notch each week:

The Workout

Week 1: 500-Meter Sprint

Rest three to four minutes.

Week 2: 400-Meter Sprint

Rest three to four minutes.

Week 3: 300-Meter Sprint

Rest three to four minutes.

Week 4: 200-Meter Sprint

Rest three to four minutes.

Instructions

“During the rest periods, you won’t be rowing; stand up and slowly pace around as you recover,” Stern says. “After completing all sprints, walk, bike or row for 10 minutes at a comfortable pace to cool down, then stretch for 10 minutes.”

TABATA Training

A Tabata is one of the simplest and most effective ways to increase your workout density: You do 20 seconds of all-out work and take 10 seconds of rest for eight rounds, or a total of four minutes. A single four-minute Tabata can torch some of your fat cache, but to get summer-shredded, you need a little extra oomph.

These workouts stack three separate Tabatas to push the limits of your fat burning to the edge. Do them on days when you’re not strength training because they are intense and will gobble up all your energy — and then some. Choose a moderate weight (12 to 16 kilograms) for your kettlebell swings and goblet squats, and for the farmer’s carry, aim for 50 percent of your bodyweight.

One thing to note: In order for a Tabata to be effective, you have to go all-out — literally giving 100 percent of all your energy possible during each 20-second work interval. Push yourself and you will be rewarded with that perfect bikini body!

TABATA A: Battle-the-Fat Tabata Stack

Cool down with 10 minutes of steady-state cardio at an easy pace, followed by 10 minutes of stretching.

TABATA B: Swing Time

Cool down with 10 minutes of steady-state cardio at an easy pace, followed by 10 minutes of stretching.