| During the upstroke the cup collapses inwards and allows air to pass by it. |
| Lift during upstroke is almost always described as small compared to that during the wing downstroke. |
| The problem here is that the upstroke should be as fast as the downstroke: this problem appears at fast tempos. |
| The basic version can also be enriched with a swinged upstroke just before the first beat. |
| Thus, lift forces exerted on the hindlimbs may explain why bats inspire during the downstroke of their wings and expire during the upstroke. |
| The backward tilt of the stroke plane elevates flight force during the upstroke by increasing the aerodynamic angle of attack. |
