Yes what it means by Karma here is repressed emotions and so forth stored in the body as tension. The meditation could be hard for some people and thats why they devised the 7 movement exercises which can cleanse the body of this tension
without the problems that could come up in meditation. The exercises are regarded as a prep for meditation or an effective therapy in their own right. I only do the exercises at present as this seems the best way to help health problems but it also
gradually counters tensions and emotions which could flood out in meditation and overwhelm you. They act to promote a steady release through the meridian system as in acupucture but cheaper and without needles. Not everyone is going to have unbearable problems with meditation, though it can be harder for some to relax this way and total true relaxation is whats needed. Gentle movement though can achieve this more easily than still sitting. That is what qigong mostly is. Even walking can be qigong if done in the right way