The Missing Link in Running Injury Research: Nonrunning Physical Activity.

SYNOPSIS: Overuse injuries from running occur when the loading stimulus exceeds the tissue-specific loading capacity. Excessive running exposure (training errors) are important precursors to injury. Despite the intuitive relationship between loading, running volume, and injury, a definitive safe loading exposure that can reliably differentiate between injured and uninjured groups remains elusive. We propose that a singular focus on running-related factors such as gait, running surface change, sudden change in running volume, frequency of running, and acute-to-chronic workload make it difficult to identify reliable mechanisms of loadrelated running injury. Given that the accumulated loading from nonrunning exercise and physical activities of daily living can impose substantial and consequential load on the musculoskeletal system, we make the case for considering loading from all sources of physical activity as a contributor to running injury. J Orthop Sports Phys Ther 2022;52(11):705-708. Epub: 9 September 2022. doi:10.2519/jospt.2022.11288.

Partial body weight support treadmill training speed influences paretic and non-paretic leg muscle activation, stride characteristics, and ratings of perceived exertion during acute stroke rehabilitation.

BACKGROUND: Intensive task-specific training is promoted as one approach for facilitating neural plastic brain changes and associated motor behavior gains following neurologic injury. Partial body weight support treadmill training (PBWSTT), is one task-specific approach frequently used to improve walking during the acute period of stroke recovery (<1month post infarct). However, only limited data have been published regarding the relationship between training parameters and physiologic demands during this early recovery phase. OBJECTIVE: To examine the impact of four walking speeds on stride characteristics, lower extremity muscle demands (both paretic and non-paretic), Borg ratings of perceived exertion (RPE), and blood pressure. DESIGN: A prospective, repeated measures design was used. METHODS: Ten inpatients post unilateral stroke participated. Following three familiarization sessions, participants engaged in PBWSTT at four predetermined speeds (0.5, 1.0, 1.5 and 2.0mph) while bilateral electromyographic and stride characteristic data were recorded. RPE was evaluated immediately following each trial. RESULTS: Stride length, cadence, and paretic single limb support increased with faster walking speeds (p⩽0.001), while non-paretic single limb support remained nearly constant. Faster walking resulted in greater peak and mean muscle activation in the paretic medial hamstrings, vastus lateralis and medial gastrocnemius, and non-paretic medial gastrocnemius (p⩽0.001). RPE also was greatest at the fastest compared to two slowest speeds (p<0.05). CONCLUSIONS: During the acute phase of stroke recovery, PBWSTT at the fastest speed (2.0mph) promoted practice of a more optimal gait pattern with greater intensity of effort as evidenced by the longer stride length, increased between-limb symmetry, greater muscle activation, and higher RPE compared to training at the slowest speeds.

Measurement of femoral torsion by ultrasound and magnetic resonance imaging: concurrent validity.

BACKGROUND: Abnormal femoral torsion has been linked to osteoarthritis in the knee as well as to patellofemoral pain. Inexpensive, valid, and reliable methods for assessing femoral torsion are needed. Ultrasound (US) is a noninvasive and clinically accessible method that can be used for the assessment of bone morphology, such as femoral torsion. OBJECTIVE: The objective of this study was to determine the concurrent validity of US for the measurement of femoral torsion with a reference method, magnetic resonance imaging (MRI). DESIGN: Repeated measurements of femoral torsion were obtained with US and MRI in a laboratory setting. METHODS: Twenty-eight people (4 men, 24 women; mean age=26.8 years [SD=4.0 years], mean body height=170.3 cm [SD=8.0 cm], mean body weight=64.7 kg [SD=9.8 kg]) participated in this study. T1-weighted axial oblique images of the femoral neck and epicondylar axis were acquired with a 1.5-T magnetic resonance system. Ultrasonographic measurements then were obtained by a tilting technique with a linear transducer that was 4.5 cm long and operated at a frequency of 10 MHz and a depth of 5 cm. RESULTS: The average angles of anteversion measured by US and by MRI were 20.7 degrees (SD=11.0) and 19 degrees (SD=11.3), respectively. The reliability, reported as the intraclass correlation coefficient [ICC (2,1)], of repeated measurements of in vivo femoral torsion by US was .98. The reliability [ICC (2,1)] of magnetic resonance image analysis was .96. The standard error of the measurement for US was 2.2 degrees, and that for MRI was 1.9 degrees. The concurrent validity of US with MRI (R(2)) was .93 (r=.96). LIMITATIONS: Obtaining measurements by US requires appropriate training before data collection. CONCLUSIONS: Ultrasound measurement of femoral torsion has high concurrent validity with in vivo MRI and may be used when an assessment of bony morphology is needed but MRI is not available.