Friday, March 25, 2016

Brian - Alex 5

Pivot

Today we started out with the pivot – taking the lead from Brian’s video clip yesterday which exposed the issue of the ski running forwards and changing edge then starting the pivot on the inside edge.



Brian can pivot fine but wasn’t relating the exercise to actual skiing. The ski has to slip sideways into the pivot in order to keep the feet directly beneath the body and avoid getting too early onto the inside edge then having to fight to contain accelerations . The other tell tale sign that Brian wasn’t doing that in pivoted turns was that he feet would end up out to the side as if he had pushed them out. The feet need to travel directly down the fall line as well as the upper body. We only worked on this briefly but Brian understood. Later on we briefly visited the Tommeuses bumps for Brian to have the opportunity put the pivot to good use – though visibility was vanishing fast by this time as snow was falling. Brian was able to avoid his usual battle with the bumps and to control his speed instead. This is clearly a step forwards. Dynamics are still used in the bumps – using the upper shoulder of the bump to check/absorb - letting the body pass over the skis over the top of the bump. The skis swing naturally because the tips are in the air until pushed down into the next hollow – and the profile of the bump assists the pivot.

Alex was stemming a bit so was asked to remain return to the original “one ski” pivot exercise. Her stem was linked to a rotation and was worse on the right leg. The main issue was that she would lean backwards with the upper body – particularly when on the right leg – the stem and rotation just being symptoms. Alex worked on tilting the upper body forwards from the hips to be able to move the centre of mass easily between the ski tips and the pole and feel the turn become tighter and more efficient.

Carving

We were on the plateau of the Grand Pré so that Alex could have a proper flat section for carving. She is now connecting well with the feeling and is able to keep the outside ski (sometimes both skis) on a carving edge in both directions. When her stance became too wide the knee would drop in and this has to be avoided! It’s better to keep the skis at hip width – moving the centre of mass across. (On flats the ChiSkiing hip change alone is enough to change edges)

Posture and ChiSkiing

Working on pivoting brought us directly to dealing with posture.

Alex: Female anatomy is different from male in that the “Q” angle of the femur is different – that is the degree the femur points inwards. The greater female “Q” angle makes edging easier, but the wider pelvis that creates this effect makes it harder to stand solidly over the top of the femur. Angulation in skiing is largely simply a question of perching the entire upper body over the head of one femur – tilting it forward from the hip joint and being able to swivel around on the ball joint. The body needs to be perched on this one hinge – not two – to move freely. In theory at least a woman would have to make a more deliberate action to get perched on a femur despite the advantage of having better grip from the better “Q” angle.  This issue probably leads to Alex’s tendency to lean backwards from the hip when pivoting into a turn. We worked to overcome this and just addressing the issue attentively appears to be enough to overcome it.

Brian had a different issue with posture and that was that he wasn’t managing to stay solidly poised on his left hip – the pelvis dropping down to the right and tending to kink the lower back to compensate. The right leg/hip connection was fine but this side tended to fall victim to another issue – a tendency to push the hips laterally and down into the turn – instead of working with the centre of mass. Both problems are connected however. If the upper body is tilted forwards from the hip and perched on the right femur/hip joint – then during a left turn the tilted upper body would turn right relative to the leg (creating angulation) – but the entire body would topple left into the turn. This is how the mechanics should be constructed – not by pushing the hips/pelvis laterally across and down into the turn – which fails to have you anchored soundly on the outside leg and fails to give you the reflexes and ski response required.

Brian’s problem eventually became clear when trying to apply the ChiSkiing hip action – counter rotating the lumbar spine. Normally this would help to consolidate a strong stance on the femur but in Brian’s case it made him fall off the hip/femur even more. The issue is really one of “pelvic tilt”. Brian has to tilt the pelvis upwards at the front to get into “neutral pelvis” and then pull the hip back (ChiSkiing). I gave both Brian and Alex the “load test” – lifting me up – and they both felt the strong reflex engagement of the core muscles when everything was in the right place – and conversely the ugly stress on the spine when not in the right alignment.  Taking this into carving Brian immediately felt the connection and strength through the core. Alex managed to continue to gain more control over her rotation and skied her first black run without even realising it and looking very effective.

Core - Centering

http://skiinstruction.blogspot.fr/p/core-principles.html

Not only is the turn controlled by the motion of the centre of mass - but all moemnt shoudl start with the core - at the centre. This "connection" through the body is vital or the body ends up just being a heap of disconnected parts all fighting each other. The first thing to do in any turn is to activate the core - and to keep it secure and let the refelexes work. Turn initiation/transition is far more effective when the core is used because it actualy lines up the bones and engages the correct muscles- adductors etc. automatically and in the right order - from the centre outwards.

Relative Motions

Moving on from postural issues I pointed out to Brian that to overcome his tendency to move the hip in laterally he had to do more than just conquer rotation and stay on the hip joint. The relative motion of the body across the skis has to be sensed as separate from the arc being made on the ground. In a basic example with the rotation now under control (pelvis facing downhill more or less) the motion of the  upper body relative to the skis is downhill and over the skis for the turn transition and uphill in into the turn to build up pressure – a sort of in and out motion in line with the fall line.

When teaching dynamics initially i avoid all of this by saying to just stand up and topple over sideways into the turn and then sideways back up out of it at the end. When angulation is created however then the upper body is not facing the same way as the skis are going so the relative motion of the upper body feels like forward and backward (in the fall line) and the detailed bio-mechanics are being dealt with at the hips. This is why attempting to create angulation by dropping the hips into a turn fails. The natural way to achieve the right movement in the hips and with the body overall is by skating. This is probably why Brian looks fine when carving – because he has based that purely on skating.

In the final scene of the video clip Brain isn't skiing as dynamically as he can because he is thinking about everything. However the points to look for are that his posture is strong, core activated, rotation controlled, forward on his skis and is constructing and using angulation correctly instead of just dropping the hips into the turn. 





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