The present invention provides in various embodiments novel, wearable systems for determining the metabolic condition of an aerobically stressed portion of tissue such as the muscle tissue of an exercising person. Generally, the systems comprise lightweight rugged detectors, worn adjacent the tissue...http://www.google.ca/patents/US6134460?utm_source=gb-gplus-sharePatent US6134460 - Spectrophotometers with catheters for measuring internal tissue
