Interventions
knee in flexion), pain
HEAT, RECRUITMENT
The intervention will be held at the Prince of Wales Hospital in Hong Kong. Participants in the intervention group will be exposed to PEMF treatment by a PEMF device (Quantum Tx, Singapore). The active PEMF does not produce heat or cause any sensation to the tissue, which allows the participants to be blinded to the treatment. Participants in the control group will receive a sham exposure with the same PEMF device. The diseased leg will be exposed to active or sham therapy for 10 min per session, and the treatment regime will run twice a week for 8 weeks, summing up 16 sessions of PEMF or sham exposure in total. The PhD candidate will be responsible to operate the PEMF machine and monitor the clinical condition of the participants. The PEMF supplier provides RFID cards generated using block randomisation to assign PEMF or sham treatment. Each participant will be allocated a unique RFID card recognisable by the PEMF machine. The PhD candidate will turn on the PEMF machine for all participants with the RFID cards. A biostatistician who does not participate in the recruitment of patients will oversee the randomisation. Hence, both participants and the research personnel are blinded, and participants will use the RFID to complete the assigned treatment without knowing which treatment they are receiving. Most participants do not report any perceivable sensations during PEMF treatment but a few participants report mild tingling or warm sensation.The procedure of PEMF treatment is shown as follows: The subject will be seated at a 90 degrees position on a chair. The solenoids of the PEMF device will be adjusted to be over the foot and ankle (Achilles tendon and lower calf muscle). The appliance options will be adjusted to 1 mT, 10 kHz on the diseased leg for 10 min. Sham pulsed electromagnetic field therapy and eccentric exercise will be used for the treatment in the sham group. The same PEMF device and the same set of eccentric exercise will be used for the control and experimental groups. Participants will not have perceivable sensations during active or sham PEMF treatment. Therefore, assessors and participants will be blinded to the PEMF applied. In addition to PEMF, all participants will perform eccentric exercise. The first step is stretching exercises for the calf muscles. The stretching is a static stretch of the gastrocnemius (knee in extension) and soleus (knee in flexion). The participants are instructed to hold these for at least 30 s and repeat each exercise three times. There will be a 1-min rest between each stretch. Three sets of 10 repetitions of the eccentric exercises will be carried out once daily for 6 weeks. After 6 weeks, the participants will be instructed to carry out three sets of 10 repetitions three times per week for 6 more weeks. The intensity of the exercise should be such that pain, or discomfort, is experienced in the last set of 10 repetitions. Every session ended with the same static stretch exercise as in step 1. Suppose a participant is unable to complete three sets of 15 repetitions. In that case, the participant is instructed to start with fewer repetitions and sets (a minimum of 2 groups of 10) and progress to the total amount as able [