This week we discuss outcomes with femoroacetabular impingement syndrome FAIS), defined as "as a clinical triad of symptoms, signs, and imaging findings related to the underlying hip pathology." There are three bony morphologies associated with FAIS: cam, pincer, and mixed. Cam morpohlogy is a bony growth on the femoral head/neck, while a pincer morphology is bony growth of the acetabulum. Mixed morphology is the presence of both cam and pincer changes. Symptoms of FAIS include hip/groin pain, pain worse with motion or certain positions, clicking/locking/stiffness, decreased hip strength/ROM, and impaired balance. The FADDIR test, commonly associated with a clinical diagnosis of FAIS, actually has poor sensitivity and specificity (41% and 47%). Early activity modifications may be necessary to manage symptoms, which involves generally avoiding repetitive hip flexion and internal rotation and limiting end-range stretching of the hip, especially in the presence of pain. Studies also demonstrate hip muscle weakness in the presence of FAIS symptoms, which could be a focus of rehab interventions. Conservative management of FAIS for a minimum of 3 months has shown to be successful in 39-82% of FAIS cases, and it is likely successful conservative management is related to the radiographic severity of morphology. Most reviews demonstrate that surgery has improved short term outcomes (<1 year) compared to physical therapy in young, active populations. Although, the return to play rate after hip arthroscopy was 85.4%, which took an average of 6.6 months. One article found that 1 in 4 athletes don’t return to previous level of sport participation after hip arthroscopy for FAIS.

The abstract can be found here: https://pubmed.ncbi.nlm.nih.gov/37650998/

As always, if you enjoy what you hear, be sure to follow us on your favorite podcast platform and on Instagram @readingrehabpod. If you have any article recommendations be sure to send them our way!

This week we discuss considerations when utilizing the limb symmetry index (LSI) as a metric for return to sport testing following ACL reconstruction. Limb symmetry index is a popular metric which compares the performance of the involved limb to the uninvolved limb during a test. Commonly, a 90% threshold is used to determine if there is acceptable levels of asymmetry. However, there are a few points to consider when utilizing this metric. First, after an ACL rupture the contralateral side also loses strength and functional capacity. Therefore, comparing to the post-surgical performance of the uninvolved side can give an artificially inflated LSI, so it is important to ground the test outcomes in normative data or benchmark data. Second, variability in movement is a "hallmark of normal function" and understand humnas, and sport, are not always symmetrical. Although, an argument can be made that the test is to see if you have the capacity to be symmetrical, which does not mean you have to be symmetrical all the time, especially at submaximal efforts. Is your maximal effort symmetric on each side? If not, then you may be more likely to be hurt. Third, biomechanical asymmetries can persist past 9 months post ACLR, so don't just look at the numbers: look at the movement strategy. Finally, assess the functional capacity across a load continuum via testing considering the end goal as the sport.

The abstract can be found here: https://journals.lww.com/nsca-scj/abstract/2024/08000/testing_limb_symmetry_and_asymmetry_after_anterior.3.aspx

As always, if you enjoy what you hear, be sure to follow us on your favorite podcast platform and on Instagram @readingrehabpod. If you have any article recommendations be sure to send them our way!

This week we discuss microscopic changes to muscle architecture following eccentric hamstring exercise. Twelve recreationally active participants in their mid-20s performed 9 weeks of eccentric hamstring training via Nordics: 3 session per week, progressively building from 4x6 to 5x8 at the end. After the 9 weeks of training, they had a 3 week detraining period. Eccentric hamstring strength during Nordics, passive fascicle length, and sarcomere length were measured at baseline, end of training, and end of detraining. Serial sarcomere number was calculated using fascicle length and sarcomere length. After the training block, there was significantly increased biceps femoris fascicle length, serial sarcomere number, volume, and knee flexion torque. There was a large effect for all of these metrics. There was a significant regional effect for fascicle length and serial sarcomere number: increased fascicle length at distal region compared to central, but increased serial sarcomeres centrally versus distally. During detraining, fascicle length decreased but remained logner than pre-training lengths. Muscle volume stayed the same and there was a decrease in strength but it was higher than pre-training. Takeaways from this article include evidence for a long-term adaptation of eccentric training being addition of sarcomeres in series which could be protective against hamstring strain injuries, and muscle architectural responses to detraining happen quickly! It would be interesting to investigate if addition of sarcomeres in series is an effect specific to eccentric training, or any specific hamstring muscle training would create this effect.

The abstract can be found here: https://pubmed.ncbi.nlm.nih.gov/39461588/

As always, if you enjoy what you hear, be sure to follow us on your favorite podcast platform and on Instagram @readingrehabpod. If you have any article recommendations be sure to send them our way!

This week we discuss tendon adaption. This review aims to define the mechanoresponses that lead to tendon adaptation, and whether or not these are positive or negative adaptations. All adaptations can be considered through a person- or tissue-level lens. Person-level adaptations involve a number of systems and are measured via athletic performance tasks, while tissue-level adaptations are isolated and unclear how they impact the whole system. Adaptation is relative to the amount of load to the tissue, and there is likely a moving, tissue-level threshold which determines if an applied load is adaptive or maladaptive. Some changes we can see in tendon are changes to cross-sectional area, stiffness, structural organization of collagen, water content, and vascularity. However, there is no clear link between changes to these characteristics and injury risk or athletic performance since these changes are seen post exercise in pathological and non-pathological tendons. Potentially, whether a tendon becomes pathological or not is more related to the systemic response to these transient, load-related changes?

The abstract can be found here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6737558/pdf/JMNI-19-300.pdf

As always, if you enjoy what you hear, be sure to follow us on your favorite podcast platform and on Instagram @readingrehabpod. If you have any article recommendations be sure to send them our way!

This week we're talking about a new classification approach for the stretch-shortening cycle! The original distinction of fast vs slow movements based on a ground contact time of 250 ms was developed in the 90's, and has not been subjected to much critique since it was introduced. Therefore, the authors aim to confirm the validity of the 250 ms threshold value by investigating factors relating to ground contact time during a drop jump test. They recruited 46 recreationally active, college age men who were sports science students to perform one day of drop jump testing and one day of shear wave elastography to determine muscle and tendon parameters, like penattion angle, stiffness, and thickness. They used a classification and regression tree analysis (CART analysis) using machine learning to analyze their 27 different variables. They created three threshold criteria based on ground contact time: short GCT < 188 ms, mid GCT 188-222 ms, and long GCT >222 ms. It is interesting that all of their thresholds are considered "fast" according to the classical distinction. Listen to the podcast to learn our critiques of this article, and possible paths forward from this!

The abstract can be found here: https://pubmed.ncbi.nlm.nih.gov/39317922/

As always, if you enjoy what you hear, be sure to follow us on your favorite podcast platform and on Instagram @readingrehabpod. If you have any article recommendations be sure to send them our way!

This week we are talking all about hip extension strength testing!

The abstract can be found here: https://www.researchgate.net/publication/366177441_You_don't_run_lying_down_-_A_novel_tool_to_assess_standing_isometric_hip-extension_strength_A_pilot_study

As always, if you enjoy what you hear, be sure to follow us on your favorite podcast platform and on Instagram @readingrehabpod. If you have any article recommendations be sure to send them our way!

This week we discuss an article looking at adherence to aerobic and muscular strengthening guidelines across 32 countries. For adults and older adults, the WHO activity guidelines are: 150-300 min of moderate aerobic or 75-150 min of vigorous aerobic activity per week, and 2 days per week of muscle strengthening of moderate intensity. It is important to meet both guidelines as this relates to various health related outcomes, like risk for cardiovascular disease and cancer mortality. The meta-analysis showed just 17% of adults over 18 years old meet both aerobic and strengthening criteria. A few trends when they grouped data by sub-populations: men were more likely to meet guidelines than women, only 8% of those with a low level of education met guidelines while 26% of those with a higher education level met guidelies, and only about 20% of people who self reported that they have good or better health are meeting guidelines. There are many socioeconomic factors that influece whether someone is able to meet guidelines, like access to transportation and facilities, infrastructure allowing active commuting, and available time to commit to exercise. Since such a small percentage of the population is actually meeting guidelines, as fitness professionals we have a duty to lower barriers to exercise and help people build healthy fitness habits so meeting guidelines may feel a little more doable.

The abstract can be found here: https://pubmed.ncbi.nlm.nih.gov/36418149/

As always, if you enjoy what you hear, be sure to follow us on your favorite podcast platform and on Instagram @readingrehabpod. If you have any article recommendations be sure to send them our way!

This week we discuss strength standards for fast vs slow linear sprinting speed in American football players. There is a known correlation between lower extremity strength/power and sprinting speed, so the authors aimed to find "how strong is strong enough?" They split a team of collegiate American football players into two groups based on body mass, with those above the median for the group classified as "heavy" and those below the median are "light." They recorded 40 yard dash time, 1RM back squat, 1RM hang clean, broad jump, and vertical jump height; and analyzed the data to determine a threshold for each of the 4 strength/power metrics which correctly classified athletes as either "slow" or "fast." Again, they determined slow vs fast relative to the group with the median 40 yard dash time being the cut-off score. In their discussion, they assert "optimal thresholds are likely to be sex-specific, population-specific, and training age specific, at a minimum." Having an understanding of which key performance indicators are relevant for the population you are working with is necessary to then know which strength/power standards are appropriate for your target population. This is just one article that can exist in a large collection of research studying "how strong is strong enough?"

The abstract can be found here: https://pubmed.ncbi.nlm.nih.gov/37815260/

As always, if you enjoy what you hear, be sure to follow us on your favorite podcast platform and on Instagram @readingrehabpod. If you have any article recommendations be sure to send them our way!