Context: Knee injury is a common problem for runners. Knee pain is a common symptom in knee injury and is associated with alterations in knee and hip muscle activation and hip joint angles. Relieving pain through intervention may help to restore neuromuscular function. Objective: To examine the effects of ice and transcutaneous electrical nerve stimulation (TENS) combination treatment on perceived knee pain, hip frontal plane angle, and muscle activation during running in individuals with experimental knee pain (EKP). Design: Crossover. Setting: Laboratory. Subjects: 19 participants (11 males and 8 females, 23.2 ± 1.9 y, 176 ± 11.6 cm, 71.5 ± 16.9 kg; right leg dominant). Interventions: Hypertonic saline was infused into the infrapatellar fat pad for 74 minutes (total 11.1 mL). Subjects underwent 2 treatment conditions (sham; ice/TENS combination). Measurements were recorded during running at 4 time points (preinfusion, postinfusion, posttreatment, and postinterval). Main Outcome Measures: Perceived knee pain on a 100-mm visual analog scale (VAS), knee and hip muscle peak electromyography (EMG) amplitude, and hip adduction angles. Results: Hypertonic saline infusion increased perceived anterior knee pain in all participants. The average of peak perceived knee pain was 28 mm on a 100-mm VAS in EKP application. While the increased perceived knee pain level stayed consistent across time in the sham session, ice/TENS combination treatment significantly reduced perceived knee pain by 35% at 6 minutes after the treatment start (p = 0.049), and the reduced knee pain lasted for 22 minutes (p > 0.05). Peak EMG amplitude of the gluteus medius was decreased by 13.5% and 14.3% (p = 0.023; p = 0.013) during running after EKP in sham and treatment sessions, respectively. However, the peak EMG amplitude was not restored to pain-free level during running after the treatment (p = 0.026). No other muscles changed their peak EMG amplitude due to EKP or treatment. Hip adduction angles during running were also not altered by EKP or treatment (p > 0.3) in both sham and treatment sessions. Conclusions: EKP increased perceived knee pain and decreased peak muscle activation of the gluteus medius during running. Ice/TENS combination treatment reduced perceived knee pain quickly, but did not restore neuromechanics during running.

Running is known to provide important health benefits. However, the incidence of injury among runners is high, particularly among novice runners, which discourages long term participation in the sport. The knee is the most commonly injured joint in novice runners. In general, aberrant frontal and transverse plane kinematics are associated with the development of knee injuries in runners. It was unknown whether the high rate of knee injury in novice runners was due to abnormal kinematics. Further, it was unclear whether these risk factors for injury could be improved. This dissertation includes four studies investigating kinematics in novice runners, how they change with training and evaluation of a running assessment. The first study compared frontal and transverse plane kinematics of female novice and experienced runners. Novice runners displayed more knee kinematics associated with injury than experienced runners, which may contribute to their higher risk of injury. The second study investigated the effects of two different training programs on kinematics of novice runners: one program consisted of 8 weeks of walking followed by 8 weeks of running, the other consisted of 8 weeks of strength/plyometric training followed by 8 weeks of running. Results demonstrated that training produced small changes in kinematics, however all types of training produced a mix of beneficial and detrimental effects. Participants who completed the study displayed better knee kinematics 8 than those who dropped out, which may have influenced their ability to complete the program. The third study sought to investigate changes in coordination of the hip and ankle joints, and their contributions to knee joint angles thought to contribute to injury. Results demonstrated that both the hip and the ankle may influence changes in knee kinematics, however the relative motion of the hip and the ankle appears to remain stable with training. In the final study, we investigated the reliability and validity of the Running Readiness Scale (RRS), as a low cost assessment of kinematics related to injury in runners. The RRS demonstrated good inter and intra rater reliability. Further, the RRS appeared to effectively discriminate between runners according to knee abduction, but not knee internal rotation.