How TECAR therapy works, explained simply.

A TECAR machine sends out a radiofrequency current, which is simply a fast-alternating electric current of the kind also used in some surgical and cosmetic devices. The Medstar device runs at around 500 kHz, meaning the current changes direction roughly five hundred thousand times every second. That is far too fast to make your muscles twitch, so it does not feel like the buzzing of a TENS machine. Instead it feels like warmth.

The current needs a path to flow through. The therapist holds an active electrode, the part on the moving handpiece, against the area being treated, and places a flat return electrode plate on another part of the body. Your tissue between the two becomes part of the electrical circuit. As the current pushes through, the tissue resists it slightly, and that resistance turns some of the energy into heat. This is the same basic idea as a wire warming up when electricity flows through it, except here the gentle warming happens inside your body where the treatment is needed.

A hot pack or a heat wrap only warms the skin and the thin layer just beneath it. To reach anything deeper, the heat has to soak slowly inward, and your body keeps moving it away through blood flow before it gets far. That is why a hot pack feels nice but rarely changes how a deep muscle or joint behaves.

TECAR is different because the heat is created within the tissue itself rather than laid on top of it. The current passes through skin, fat, muscle, tendon, and joint structures, and the warming happens along that whole path. This lets the clinician warm areas that a surface heat source struggles to reach comfortably, such as a deep hip muscle or a thick part of the calf, without having to make the skin uncomfortably hot.

TECAR works in two settings, and the therapist chooses based on what is being treated. Capacitive mode is aimed at softer, water-rich tissue closer to the surface, such as muscle. Resistive mode is aimed at denser, deeper tissue with less water, such as tendon, ligament, and bone. The difference comes down to how the electrode is built and where the energy concentrates.

In a real session the therapist often moves between both modes over the same area. We cover this in much more depth on the capacitive versus resistive mode page.

The deep warmth is not the goal by itself. It is a way to put the tissue into a better state for the rest of treatment. When tissue warms, several useful things tend to happen. Local blood flow increases, which brings more oxygen and helps clear the by-products of injury. Tissue becomes more extensible and pliable, meaning it stretches and moves more easily, so stiff areas loosen. Protective muscle tightness, often called muscle guarding, can ease, which lowers the resistance the therapist feels during hands-on work.

The point of all of this is timing. A warmer, more pliable, less guarded area responds better to the manual therapy, stretching, and strengthening that come next. TECAR is used to open a window where the active part of your physiotherapy plan can do more. It is one tool among several, alongside options such as shockwave and laser therapy, and your therapist decides whether it fits your specific injury.

It is worth being honest about what is well established and what is not. The heating effects of a radiofrequency current and the basic physical effects of warming tissue, such as wider blood vessels and easier movement, are well understood and have a long history in physiotherapy under the older name diathermy, which simply means deep heating. Heat-based treatment is a normal part of musculoskeletal care.

Some manufacturers also claim TECAR produces helpful effects at the cell level that are not caused by heat. Those non-thermal claims are still being studied and are not settled, so we do not lean on them. If you want a clear-eyed look at the current evidence, see our TECAR evidence and research page. For general, plain-language guidance on physiotherapy and managing pain, HealthLinkBC is a reliable starting point: HealthLinkBC. TECAR is not a substitute for assessment and advice from a registered physiotherapist, and it is not the right tool for every problem.