Plank
The plank is an isometric hold on the forearms and toes that trains the abdominals, lower back, and shoulders to keep the body rigid. It is the simplest core exercise in the NSW guide and the one with the longest holds, reaching 60 seconds per set by the end of the program.
How to Perform It
Lie face down with your legs straight and your feet together. Place your forearms on the floor with your elbows directly below your shoulders, then raise your body so your weight rests on your toes and forearms. Hold the position by statically contracting the core muscles and keep a straight line from heels to shoulders. Do not let the hips sag or pike upward. The guide offers two variations once the basic hold is solid: lift each arm and leg off the floor one at a time and hold each for several seconds while the torso stays still, or hold one arm and the opposite leg off the floor at the same time.
Why It Matters for BUD/S
The guide lists the plank as a primary core exercise because it teaches the trunk to resist movement rather than create it. That is the demand of most of BUD/S: holding a rigid body in the front-leaning rest, keeping a straight line during hundreds of push-ups, and staying flat in the water during the swim. A plank also trains the transverse abdominis, the deep muscle the guide says you should activate during every core session. The guide suggests coughing before a core exercise to feel that muscle contract, then keeping it engaged through the hold.
Where It Sits in the 26-Week Plan
Planks land on the four core days each week: Monday and Friday paired with upper body lifting, and Wednesday and Thursday paired with the push-up, sit-up, and pull-up block. The prescription starts at 2 sets of 30 seconds in weeks 1 through 6, moves to 2 sets of 45 seconds, then to 3 sets of 40, 50, and finally 60 seconds in weeks 22 through 26. Total time under tension roughly triples across the program. Work up to each block's numbers rather than forcing them, and add the arm and leg lift variations only when the basic hold stays straight for the full time.
Prescription by program week
| Weeks | Sets x reps |
|---|---|
| 1-6 | 2 x 30 sec |
| 7-11 | 2 x 45 sec |
| 12-16 | 3 x 40 sec |
| 17-21 | 3 x 50 sec |
| 22-26 | 3 x 60 sec |
End the set when your hips drop, not when the clock runs out. A shorter perfect hold builds more than a long sagging one.
Related Terms
Core exercises in the NSW preparation program target the trunk stabilizers — abdominals, obliques, lower back, and hip muscles — through a progressive rotation of planks, bridges, bird dogs, supermans, and side planks. These exercises build the trunk stability that supports every movement in BUD/S, from running to swimming to log PT.
The side plank is an isometric hold on one forearm and the edge of the feet that trains the obliques and the muscles along the side of the hip. The NSW guide prescribes it per side, so every set is performed twice, once on the left and once on the right.
Push-ups are a foundational upper-body calisthenics exercise and one of the five scored events in the Physical Screening Test (PST). In BUD/S preparation, push-up training follows a progressive volume approach where daily targets scale based on the candidate's most recent PST max.
The superman is a prone extension exercise in which you lie face down and lift both arms and both legs off the floor at the same time. It trains the spinal erectors, glutes, and rear shoulders, and it is the only core exercise in the NSW progression that is programmed in low reps rather than long holds or high counts.
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