Part of these sets

This exercise rarely works alone. It appears in the following routines, where it is sequenced alongside the others that support it.

What it works

Primary muscles

Lumbar multifidus and erector spinae
Gluteus maximus, on the lifting leg

Also involved

Deep abdominals, holding the pelvis level
Shoulder stabilisers of the reaching arm

Equipment: None. A mat or folded blanket under the knees.

How to do it

1
Start on hands and knees, hands under shoulders, knees under hips, spine in a relaxed middle position. Imagine a full cup resting on your lower back.
2
Breathe out, lightly firm the trunk, and reach one arm forward and the opposite leg back until both are roughly horizontal.
3
Reach long rather than high: fingertips forward, heel back. The pelvis stays level and the cup does not spill.
4
Hold for five to ten seconds, breathing normally.
5
Return with control and swap sides. Slow and boring is correct.

How much to do

5 to 8 repetitions each side, holding 5 to 10 seconds

3 to 4 times a week

Endurance is the goal, so end each set one repetition before the wobble starts. Sloppy extra repetitions train the wobble.

Stop and get assessed if

Stop and get assessed if the exercise provokes back pain that lingers afterwards, sends symptoms into a leg, or if one side stays markedly weaker or clumsier despite practice. A working ache in the back and hip muscles that fades quickly is the intended feeling.

Common mistakes

Lifting the leg too high: Anything above horizontal comes from the lower back, not the hip. The back arches, the pelvis tips, and the exercise stops training stillness.
The trunk swaying or the hips tipping: The stillness is the exercise. If you tip, the lever is currently too long for your control: use a regression rather than practising the sway.
Head dropping or craning up: The neck is part of the spine being trained. Keep your eyes on the floor just ahead of your hands so the whole line stays level.
Holding the breath through the hold: Breath-holding fakes the stability, and the hold collapses when the air runs out. Keep breathing so the trunk muscles themselves learn to do the work.

Making it harder

Lengthen the holds towards ten seconds without the pelvis tipping.
Link repetitions without resting the hand and knee on the floor between them, touching down only lightly.
Draw a slow, small square with the reaching hand and heel while the trunk stays absolutely still.

Making it easier

Move one limb at a time, just the arm or just the leg, until the trunk stays quiet throughout.
Keep the fingertips and toes sliding along the floor rather than lifting, which shortens the lever while the pattern is learned.

Bird Dog