Who these sessions are for

These are three short sessions for the abs and the rest of the trunk, written to sit on top of a plan you already follow: full body, upper/lower or push pull legs in the gym, or training at home. Each is four exercises of three sets and takes about 20 minutes. Session A needs a strip of floor, B a bar to hang from, C a cable station and a kettlebell.

They will make your abs stronger. They will not uncover them. In a 6-week study, 24 sedentary adults were split into two groups: one did seven abdominal exercises, two sets of 10, five days a week, and the other did nothing. The exercise group lost no more body fat, waist or skinfold than the other, although by the end it managed more curl-ups: 47 against 32 (Vispute and colleagues, 2011). When 11 young adults trained one leg for 12 weeks, the fat they lost came off the arms and the trunk, not the trained leg (Ramírez-Campillo and colleagues, 2013).

Whether your abs show depends on how much fat covers them, and that is the work of your diet and your whole week of training. The fat loss workout plan is written for that goal; these sessions are for a stronger trunk.

How much ab work your plan already has

Most programs in Trenno already give the abs a few sets of their own. Counted from their rows, by the exercises our exercise library files under Abs:

Program Ab sets a week Add
Beginner Full-Body Barbell, 3 days 9 One session
Intermediate Upper/Lower, 4 days 6 One session
Body-Part Split, 5 days 6 One session
Intermediate Push Pull Legs, 3 days 3 One session
Lower Body and Glutes, 3 days 0 One session
Home HIIT, No Equipment, 3 days 12 None needed

About 10 to 20 hard sets per muscle group a week is the range our sets guide works from. A session here is 12 sets, so one a week takes each of the first five programs to between 12 and 21 ab sets. Home HIIT and Suspension Full-Body give the abs 12 sets a week of their own.

Where to put it:

  • After the last exercise of a lifting day, never before it. Squats, deadlifts and overhead presses need a trunk that can still brace hard.
  • Or on a day off, as a session of its own.
  • Rotate the three if your kit allows: A one week, B the next, C the third. Otherwise keep to the one you can do.

The three sessions

Each is four exercises of three sets, with a minute of rest after every set. The rows are the app’s own, as they stand in Explore.

Session A: the floor, no equipment

This is the “Quick Core, 20 min” routine in Trenno’s Explore, unchanged.

Exercise Sets Rest
Plank 3 × 45 sec 1:00
Hollow Rock 3 × 12 to 20 1:00
Bicycle Crunch 3 × 15 to 25, both sides counted together 1:00
Dead Bug 3 × 10 to 15 1:00

Session B: a pull-up bar

This is “Abs on the Bar” in Explore without its Bicycle Crunch, which Session A already has.

Exercise Sets Rest
Hanging Knee Raise 3 × 8 to 15 1:00
Reverse Crunch 3 × 12 to 20 1:00
Side Plank 3 × 30 sec a side 1:00
Hollow Rock 3 × 10 to 20 1:00

Session C: a cable and a kettlebell

This is “Lifter’s Core” in Explore without its Hanging Knee Raise, which Session B already has.

Exercise Sets Rest
Cable Crunch 3 × 10 to 15 1:00
Ab Wheel Rollout 3 × 6 to 12 1:00
Cable Pallof Press 3 × 10 to 12 a side 1:00
Kettlebell Suitcase Carry 3 × 30 m a side 1:00

The three cover the jobs the trunk does. The crunches and the raises curl it. The plank, the dead bug, the hollow rock and the rollout keep the lower back from arching. The side plank, the Pallof press and the carry, 30 meters (about 33 yards) with the bell in one hand, keep it from bending or turning to one side.

If you would rather not crunch at all, Explore has “Core Without Crunches”: the Dead Bug, the Bird Dog, the Side Plank, the Plank and the Glute Bridge, 15 sets.

Sets, reps, rest and effort

  • Rest a minute after every set. That is what the four routines prescribe, and it is what holds a session near 20 minutes.
  • End each set with one or two good reps left. A hold ends when the position breaks: the hips sag in the plank, the lower back lifts off the floor in the dead bug or the hollow rock.
  • One-sided work counts each side. Do the full time or the full count on each side in the side plank, the Pallof press and the carry. In the Bicycle Crunch, the count is both sides together.

High reps are fine for the abs, as for any muscle. A meta-analysis of 21 studies found similar muscle growth from light and heavy loads when every set was taken to failure, while heavy loads built more maximal strength (Schoenfeld and colleagues, 2017). What matters is that the last reps of a set are hard.

How to progress

Use double progression, as in our progressive overload guide: stay on an exercise until every set reaches the top of its range, then make it harder. With a cable or a kettlebell, harder is the next weight. On the floor and on the bar, it is the next step of the ladder:

Exercise Easier Harder
Plank Kneeling Plank Body Saw Plank
Side Plank Bent-Knee Side Plank Side Plank with Raised Leg
Hollow Rock Hollow Hold Arms overhead, legs lower
Hanging Knee Raise Lying Leg Raise Hanging Leg Raise
Ab Wheel Rollout Wheel Rollout with Wall Support Standing Wheel Rollout

An example on the Hanging Knee Raise, 3 sets of 8 to 15:

Week Reps per set Next session
1 10, 9, 8 same
2 12, 10, 9 same
3 13, 12, 11 same
4 15, 14, 13 same
5 15, 15, 15 Hanging Leg Raise
6 8, 7, 7 on the leg raise same

Start the harder version at the bottom of the range, and climb again. Rather than holding a plank for minutes, move up the ladder once 45 seconds is easy.

Substitutions

If Instead of Do
There is no bar Hanging Knee Raise Lying Leg Raise
There is no cable Cable Crunch Reverse Crunch
There is no cable Cable Pallof Press Band Horizontal Pallof Press
There is no ab wheel Ab Wheel Rollout Stability Ball Rollout
There is no kettlebell Kettlebell Suitcase Carry Dumbbell Suitcase Carry

Keep the sets, the reps and the rest of the row you replace.

How long a session takes

Counted at about 40 seconds a set of reps, each side of a one-sided set, the holds as written and a minute of rest after every set: Session A takes about 20 minutes, B about 21, and C about 24, because two of its exercises are done one side at a time. Add a couple of minutes to set the cable. Core Without Crunches takes about 26.

Common mistakes

  • Training the abs to lose belly fat. The studies above found no local fat loss. Train them for strength; lose the fat through the whole week.
  • Doing them first. A trunk tired from 12 sets braces worse under a heavy squat.
  • Swinging on the bar. A swing lifts the legs for you. Hang still, then raise.
  • Letting the lower back arch in the hollow rock, the dead bug or the rollout. Shorten the range until the back stays down.

FAQ

How often should I train abs?

Once a week on top of any of our programs, which already give the abs up to 12 sets a week. Twice suits a plan with no ab work at all, such as Lower Body and Glutes, when you want the abs to lead for a while.

Do squats and deadlifts train the abs?

They make the trunk work hard to stay still under the bar, which is valuable. They never curl it or turn it, which is why most of our programs add a few ab sets and these sessions add more.

Will ab exercises burn belly fat?

No. Six weeks of ab exercises five days a week changed neither body fat nor waist size in the study above. Fat loss comes from the whole week: food, training and daily movement.

How many reps are best for abs?

The ranges in the tables, from 6 to 25, as long as the last reps of each set are hard. A set you could repeat twice over builds little.

Can I train abs every day?

You can, but these sessions are written for one or two days a week. The abs grow from hard sets like any other muscle, and recovery is part of the plan.

Sources

All four routines are in Trenno’s Explore. Start one as it is, or take a copy to drop an exercise, as Sessions B and C do. The clock on the workout screen has a timer and a stopwatch for the holds, and the rest timer starts when you tick a set.