Early resistance exercise sessions and home program

Weekly sessions introducing resistance exercises and monitoring the patients acceptability. The exercises are isometric contractions, seated heel-rise and elastic band. The patient register the amount of exercise in a home exercise journal. To protect the tendon while doing range of motion of the foot, dorsiflexion is restricted beyond neutral (0 degrees of dorsiflexion). The load on the strength exercises will progress from isometric contraction without external load to strengthening exercises with 10-20 RM (RM: Repetition Maximum). Each strength exercise can progress with added weight or stronger elastic band. The Borg scale is used to guide the patient to progress or regress the load in each exercise. The recommended level being "easy" to "hard" (2-5/10). It is emphasised that the exercises must not cause sudden or severe pain in the tendon, but muscle soreness is to be expected.

The participants will rate their acceptability (willingness) to perform the exercises on a 7-point Likert scale ranging from "very unacceptable" to "very acceptable". This is not a measure of whether the patient's symptoms have improved to normal physical function or any other satisfactory level at the specific time, but if it matches, their expectations of the content of an exercise program in this early phase and how they tolerate performing the exercises. The intervention program is categorised as "Unacceptable" if rated as the three lower scores ("very unacceptable" to "slightly unacceptable") and categorised as "Acceptable" if rated as the four higher scores ("neither acceptable or unacceptable" to "very acceptable"). The exercise program is considered feasible if acceptability of the exercise program is 80%. Defined as: ≥13/16 patients will rate the acceptability of the intervention as "acceptable".

The participants will register the number of training sessions and exercises they perform each day in a training journal. The compliance is measured as the mean number of exercise sessions they perform. The timeframe will be from the day they start the exercises to the end of week 9. The exercise program is considered feasible if the adherence to the exercise program is 50%. Defined as: ≥13/16 patients will perform ≥ 50% of the exercise sessions possible from start to end of week 9.

The Tampa scale of Kinesiophobia (TSK) is a questionaire consisting of 17 items concerning pain and kinesiophobia and has 4 answers from "Strongly disagree" to "Strongly agree". During the exercise intervention period and at 3 months follow,up the patients will fill out the score and subsequently they are asked to rate the appropriateness of the score on a 7 point Likert scale ranging from "strongly disagree" to "strongly agree".