A guest asks you what a deadlift "actually works". You could list muscles for a minute and still not answer the useful question, which is what the movement is for and why the body organises itself that way. Instructors who think in patterns coach better than instructors who think in muscles.
The major muscle groups
| Region | Key muscles | Main job |
|---|---|---|
| Posterior chain | Glutes, hamstrings, erector spinae | Hip extension, holding you upright |
| Anterior thigh | Quadriceps | Knee extension |
| Chest and shoulders | Pectorals, deltoids | Pushing, arm elevation |
| Back | Latissimus dorsi, trapezius, rhomboids | Pulling, scapular control |
| Core | Rectus abdominis, obliques, transversus abdominis, deep spinal stabilisers | Resisting unwanted movement of the trunk |
| Arms | Biceps, triceps | Elbow flexion and extension |
| Lower leg | Calves, tibialis anterior | Ankle drive, balance |
The planes of movement
- Sagittal — forward and back. Squats, lunges, presses, rows. Most gym work lives here.
- Frontal — side to side. Lateral raises, side lunges, lateral band walks.
- Transverse — rotation. Throwing, twisting, most sport, most real life.
Programmes that stay entirely in the sagittal plane leave a guest strong in a straight line and unprepared for anything else. Add frontal and transverse work deliberately.
The compound patterns
Everything useful you will ever coach is a version of one of these six.
| Pattern | Examples | Cue that usually helps |
|---|---|---|
| Squat | Goblet squat, box squat, split squat | Knees track over toes; chest stays proud |
| Hinge | Deadlift, Romanian deadlift, hip thrust, kettlebell swing | Push the hips back, not the knees forward |
| Push | Press-up, dumbbell press, overhead press | Ribs down, elbows around 45 degrees |
| Pull | Row, lat pull-down, band pull-apart | Lead with the elbow, not the hand |
| Carry | Farmer carry, suitcase carry | Tall, braced, breathe |
| Rotate / anti-rotate | Pallof press, cable chop, dead bug | Resist the twist before you create one |
Build a session from patterns, not from body parts. A guest with 30 minutes gets far more from a squat, a push, a pull and a carry than from an arm-focused circuit.
Mobility, flexibility and the core, briefly
Flexibility is passive range; mobility is usable, controlled range. Guests generally need mobility. And the core is not a six-pack — it is a stabiliser, and it is best trained by resisting movement (planks, dead bugs, Pallof presses, carries) rather than by endless flexion. Crunches by the hundred are a poor use of a guest's time.
Onboard Notes
- Onboard, the carry pattern is a gift: it needs almost no space and it is hard to do badly.
- Rotation work with a band is ideal at sea — no falling load, no room needed.
- Coach the pattern, then the load. A guest who cannot hinge with an empty hand should not be holding a kettlebell.
- Preparatory study only. Nothing here qualifies you to instruct. Leading guests requires an accredited qualification and professional indemnity insurance.