This study will look to evaluate the feasibility of a backwards downhill running program as an option for the treatment of Achilles tendinopathy in runners. It is known that exercise on the Achilles tendon during elongation (eccentric exercise) improves tendon function after injury. However, during recovery, the patient is required to stop tendon-loading activities such as jumps and sprints. Therefore, during recovery, athletes decline in physical fitness.

Backward running on a negative slope can achieve a biomechanical load similar to eccentric exercise without decreasing physical fitness.

The study was a prospective, single-arm feasibility study. Participants were patients who met the entry criteria and were referred to the Meuhedet health service Physical Therapy outpatient clinic, Jerusalem, from September 2019 to February 2020. The sample size was based on previous recommendations for pilot and feasibility studies (Julious 2005; Billingham, Whitehead, and Julious 2013). Inclusion criteria were: AT that was clinically determined by an orthopedic surgeon (E.S) according to nontraumatic pain and tenderness at the Achilles tendon and report of decreased activity levels secondary to Achilles pain; a history of running for at least one session a week in the past three months; age > 18 and < 70. Exclusion criteria were having other lower extremity injuries; prior treatment with eccentric exercise or currently receiving Physical Therapy for AT; received a steroid injection into the tendon in the three months prior, or underwent Achilles tendon surgery.

Participants received a total of nine treatment sessions, twice a week for a total of five weeks. Each treatment consisted of backward walking / running over an 8º negatively inclined treadmill. (Landice L7 Rehabilitation treadmill, New Jersey, USA) with a warmup and a cooldown on a stationary bike. A detailed description of the protocol is presented in Table 1. As backward locomotion on a treadmill was novel for all participants they were advised to hold the treadmill handles during the adjustment period (treatment sessions 1-3). Participants were also instructed to refrain from specific sports which involve continuous jumping and forward running throughout the intervention period. Patients were informed that if they do not feel comfortable with the training protocol, they could terminate their participation at any point.

Assessments took place at baseline, pretreatment four, pretreatment six, and at a separate meeting after treatment nine

Inclusion Criteria:

1. Distinct tenderness of Achilles tendon with no pain in the neighboring structures.
2. Nontraumatic diffuse pain in the posterior calf with local tenderness in the Achilles tendon.
3. A history of running for at least one session a week in the past three months.
4. Age > 18 and < 70

Exclusion Criteria:

1. Achilles pain longer than six months.
2. Patients with an additional lower extremity injury unable to bear full weight on the limb.
3. Patients who are currently receiving physical therapy for Achilles tendinopathy, have received a steroid injection into the tendon in the three months prior, or underwent Achilles tendon surgery.