I disagree with the recommendation of Jendrassik’s manoeuvre (clenching the teeth or wringing the hands) to reinforce the reflexes as recently recommended in the British Medical Journal.1 These manoeuvres only allow two or three strikes before the patient becomes attuned.

For reinforcement I found it useful to tell the patient to close their eyes and they were thus unprompted about the impending strikes. If this failed then also asking the patient to do serial sevens totally removes conscious influences on the reflexes. In this way one can use many alternating strikes to compare the two sides and to do this it is useful to find the minimal impact on one side and then transfer the same impact to the other side (hitting both sides vigorously tends to elicit a full response even if there is a deficit on one side).

When targeting a tendon it is important that the tendon hammer head is at right angles to the tendon, thus making sure that the tendon is hit.

I found that brisk tendon reflexes with downgoing plantar reflexes in a euthyroid patient could provide an opportunity to discuss anxiety issues in a seemingly calm patient. “Those reflexes are brisk. Sometimes people who seem calm on the surface often hide their anxieties “Are you like the proverbial duck, calm on the surface but paddling like mad below the surface?”
Reference
Testing the Reflexes. Lees A, Hurwitz B. BMJ 2019;366:14830
Philip D Welsby