Pre-stretch is a light preliminary tension applied to the string before or during stringing. This procedure can be useful especially with strings that tend to lose tension quickly over time due to material plasticization or poor dynamic stability.

The decision to use pre-stretch is always a personal one and depends on the player, technician, or stringer. Generally, when pre-stretch is applied, it is advisable to reduce the stringing tension by the same percentage in order to maintain a balanced playing response.

Some practical examples help clarify the concept:

• 20 kg with 10% pre-stretch → recommended final tension: 18 kg
• 25 kg with 10% pre-stretch → recommended final tension: 22.5 kg
• 25 kg with 20% pre-stretch → recommended final tension: 20 kg

The main advantage of pre-stretch is greater tension stability over time, as the string relaxes less during the first hours of play.

On the other hand, pre-stretch makes the string stiffer. The alignment of the material’s molecular chains increases firmness, with effects that vary depending on string type, material, and gauge.

For this reason, pre-stretch should be considered a useful but delicate tool: it improves consistency but also alters feel and comfort.