Tell readers what the nominal configuration is (i.e. when all angles are zero)

[moorepants]

Reviewer 3 (Srinivasan):

Figure 4, caption. Perhaps indicate in your caption what the ‘zero’ for your angles correspond to? Alternatively, what does the ‘calibration pose’ correspond to? I believe that the convention used is different from, for instance, David Winter’s data (which is, of course, fine). I believe -90 degrees ankle corresponds to quite standing in this figure, whereas in Winter’s data, 0 degrees ankle is close to quiet standing.

[moorepants]

The joint angles are defined such that when all angles are equal to zero the body is fully extended (including the vector from heel to toe being aligned with vector from knee to ankle). So these vectors are all aligned:

• shoulder to hip
• hip to knee
• knee to ankle
• heel to toe

The angle and moment sign convention is such that all of these are positive: hip flexion, knee flexion, ankle plantar flexion.

The calibration pose (t-pose) may not be described well. From the nominal position defined above:

• ankle dorsiflexed to ~90 deg
• hip abduction ~30 deg
• shoulder abduction (if nominal is vector from shoulder to hand aligned with above) ~45 deg