Continued Activity During Rehabilitation in Patients With Patellar Tendinopathy

• Adverse Events[ Time Frame: Number over first year of study recruitment ]
  The number and types of adverse events occurring in either group during study participation.
• Knee Injury and Osteoarthritis Outcome Score - Quality of Life subscale (KOOS-QOL)[ Time Frame: Change over time with evaluations at baseline, 6-weeks, 12-weeks, 6-months and 1-year ]
  The Knee Injury and Osteoarthritis Outcome Score - Quality of Life subscale (KOOS-QOL) will be used to assess the impact of knee injury on quality of life. The KOOS-QOL is a subscale of the Knee Injury and Osteoarthritis Outcome Score (KOOS). Scores range from 0 to 100 with 0 indicating extreme detrimental effect on quality of life and 100 indicating no effect on quality of life.
• Tampa Scale of Kinesiophobia (TSK)[ Time Frame: Change over time with evaluations at baseline, 6-weeks, 12-weeks, 6-months and 1-year ]
  The Tampa Scale of Kinesiophobia (TSK) will be used to measure participants fear of movement and re-injury (kinesiophobia). Scores on the TSK range from 17 to 68 with 17 indicating minimal to no fear of movement and re-injury and 68 indicating very high fear of movement and re-injury.
• Pain Catastrophizing Scale (PCS)[ Time Frame: Change over time with evaluations at baseline, 6-weeks, 12-weeks, 6-months and 1-year ]
  The Pain Catastrophizing Scale (PCS) will be used to assess patients pain catastrophizing. Scores on the PCS range from 0 to 52 with 0 indicating no pain catastrophizing and 52 indicating high levels of pain catastrophizing.
• Physical Activity Scale (PAS)[ Time Frame: Change over time with evaluations at baseline, 6-weeks, 12-weeks, 6-months and 1-year ]
  Physical activity level will be measured using the Physical Activity Scale (PAS). Scores on the PAS range from 1 to 6 with 1 indicating "Hardly any physical activity" and 6 indicating "Hard or very hard exercise regularly and several times a week".
• Numeric Pain Rating Scale (NPRS)[ Time Frame: Change over time with evaluations at baseline, 6-weeks, 12-weeks, 6-months and 1-year ]
  Patellar tendon pain will be assessed using the numeric pain rating scale. Participants are asked to verbally rate their pain on a scale of 0 to 10 with 0 indicating "No pain at all" and 10 indicating the "Worst pain imaginable".
• Mechanical Pain Threshold[ Time Frame: Change over time with evaluations at baseline, 6-weeks, 12-weeks, 6-months and 1-year ]
  Pain Pressure Threshold
• Depression, Anxiety and Stress Scale (DASS-21)[ Time Frame: Change over time with evaluations at baseline, 6-weeks, 12-weeks, 6-months and 1-year ]
  Participant's depression, anxiety and stress levels will be assessed using the Depression, Anxiety and Stress Scale (DASS-21). The DASS-21 consists of three subscales, (1) Depression, (2) Anxiety, and (3) Stress. Scores for each subscale range form 0 to 42, where 0 indicates normal levels of the measured trait (depression, anxiety or stress) and 42 indicates extremely severe levels of the measured trait.
• Compliance with Activity Modification[ Time Frame: Average compliance rate for each group over first year of study recruitment ]
  Training log - Number of times pain exceeded pain threshold for either group

This pilot study will evaluate the feasibility of pain-guided activity modification during rehabilitation for patellar tendinopathy. The information provided will be utilized to conduct a larger randomized clinical trial to determine if there is a difference in recovery from patellar tendinopathy during rehabilitation between individuals that use pain-guided activity modification and those that halt all painful activities. Recovery from patellar tendinopathy will be assessed using pain ratings, tendon-specific outcome measures, tendon structure, tendon mechanical properties, and muscle function.

• Other: Exercise Treatment
  Exercise treatment will consist of squatting and knee extension exercises, designed to progressively load the patellar tendon (Heavy-Slow Resistance protocol). A pain-monitoring model is used to guide exercise loads. As the protocol progresses, exercise load is increased while repetitions are decreased.
• Other: Pain- Guided Activity Modification
  Participants sports participation and physical activity will be guided by the Pain-Monitoring Model. Using the Pain-Monitoring Model, patients may participate in activities that cause patellar tendon pain, as long as pain does not exceed 5/10 on the numeric pain rating scale (NPRS) (0 = No pain, 10 = Worst pain imaginable) during or immediately after activity. Additionally, pain should return to pre-activity levels by the following morning and pain should not increase from week-to-week.

• Experimental: Pain-guided Activity Modification
  Participants in the Pain guided Activity Modification group will receive an exercise program consisting of progressive patellar tendon loading exercises Outside of physical therapy treatment, these participants will modify activity based on the Pain-Monitoring Model.
• Active Comparator: Pain-free Activity Modification
  Participants in the Pain-free Activity Modification group will receive an identical exercise program to the Pain-guided Activity Modification group. However, participants will not be allowed to participate in activities that cause patellar tendon pain outside of physical therapy treatment.