Here’s a brief summary of the study:

Study Purpose:

• To determine the presence of a relationship between hamstring length and PFJ stress at 3 specific knee joint angles of flexion.

Study Population:

• 16 recreationally active males divided into two groups based on knee joint angle-measured hamstring length.

Methodology:

• A biomechanical model incorporating knee joint angle, knee extensor moment, and PFJ contact area was used to quantify PFJ stress.
• MRI and 3D motion analyses were also utilized in this study.
• A one-way ANOVA to determine the variations in PFJ stress between the 2 groups (with and without reduced hamstring length) was used.

Main Findings:

• Patellofemoral Joint stresses differed significantly between the two groups at specific angles of knee flexion.
• No significant differences in hip angles between the two groups.

Clinical Application:

• This study demonstrated that subjects with reduced hamstring lengths have increased PFJ stress during various positions of the squatting movement.  As a result, such a decrease in length MAY contribute to the pathogenesis of various conditions relating to the knee.
• These results enable us to consider another factor when managing those with knee pathology.

For a complete and “evidence-informed” understanding of the study, check out my review. I have obviously left out specifics from this study in this post as Research Review Service is a paid membership site. However, if you would like more information, please do not hesitate to ask.

Photo source

.

*note: the above link for RRS is an affiliate link

No related posts.

Related posts brought to you by Yet Another Related Posts Plugin.

.

Have you missed the boat?

.

I understand that you may not be a new graduate and therefore, may not have been exposed to the latest research but even those magazines that you’re getting your training programs from have published articles on this issue.

So in the event that you have unwillingly missed the boat, here are a series of articles from Mike Robertson that should help you understand the implications of what you are prescribing.

.

UNDERSTANDING YOUR ABS

UNDERSTANDING YOUR ABS, PART II

.(click on the above links)

Mike will be lecturing in Vancouver in December so if the above articles tickled your fancy, you may want to attend. I’m sure it will be a great presentation. Click here for more information.

No related posts.

Related posts brought to you by Yet Another Related Posts Plugin.

Sure surgical interventions are dependent on the goals and functional capacity of the individual but most of us generally correlate surgery with ACL injuries, no? I mean, I thought PCL and MCL injuries were the only ones that didn’t require an operation (that was sarcasm by the way).

Well Roos (a prominent knee researcher) and colleagues recently published a paper on non-elite athletes, outlining that there were relatively little differences between in functional capacity and return to physical activity between their control and experimental groups.

Here’s an excellent summary of the study’s findings.

Surgery Might Not be Needed for ACL Tears.

To read the full paper, click here

No related posts.

Related posts brought to you by Yet Another Related Posts Plugin.

Let me tell you why:

• POSTURE: In order to jump rope efficiently and for long periods of time, it is important that one maintain an ideal posture throughout the exercise. As such, improving ones posture will effectively facilitate a neutral spine position in each of the Cervical (neck), Thoracic (mid/upper back), and Lumbar (low back) regions, thereby promoting proper function of each of the active, passive, and neural components of spinal stability. Perfect posture promotes movement efficiency (see MovementU) and therefore, training to maintain ones posture may translate into increased efficiency during running.

• BILATERAL SHOULDER EXTERNAL ROTATION: In general, the glenohumeral joint is isometrically held in a bilateral external rotation position throughout the jump rope exercise. Reinold et al. recently demonstrated that the concentric bilateral external rotation exercise facilitated scapular control without the need for arm elevation, while simultaneously utilizing a good lower trapezius to upper trapezius activation ratio. While isometric contractions certainly differ from concentric contractions, one may hypothesize that isometrically maintaining the shoulder girdle complex in this position may facilitate optimal patterning of the thoraco-scapulo-humeral joints…especially  since isometric contraction of the glenohumeral external rotators play an important role in force coupling with the powerful pectoralis major during the early pull phase of swimming (this force coupling helps keep the head of the humerus centered within the glenoid fossa: aka dynamic stability). Similarly, bilateral external rotation may  also play a rehabilitative role in those athletes presenting with signs of Type 1 “SICK” scapulae (inferior prominence of the medial border) for the same reasons noted above.

• ECCENTRIC HIP ABDUCTION: During the stance phase of running, the hip plays a contributing role in absorbing ground reaction forces sustained by the body upon impact. This is so via eccentric contraction and control of the abductors of the hip (i.e. Gluteus Medius). Each “foot contact” of single and alternating leg rope jumping is not dissimilar to the stance phase of running as the hip abductors are called into action with every repetition. As such, incorporating rope jumping in the off season may result in preventing dynamic valgus (aka “buckling in”) of the knee, thereby minimizing energy leakage while running. The end result: A more efficient, powerful running gait.

• Low Intensity Stretch Shortening: Plyometric exercise has been scientifically demonstrated to be effective in improving performance and economy in certain distance runners. Since, jumping rope can be viewed as a lower intensity form of plyometric exercise, improving the stretch shortening capabilities of the deep flexors of the foot and ankle may translate into similar effects. At the very least, since mid- and forefoot runners tend to have a single and greater peak force upon impact (as opposed to the double peak seen in rearfoot strikers), performing low intensity stretch shortening exercise may strengthen the ability of the lower leg musculature to act as shock absorbers, subsequently minimizing chances of dynamic instability (i.e. overpronation) and/or tendinopathy (i.e. of the achilles).

Unless I am mistaken, the efficacy of jumping rope for triathlon performance has yet to undergo scientific investigation. Therefore, definitive conclusions from the above statements must certainly not be made. However, as with many currently performed exercises, the theoretical rationale for rope jumping as an off season exercise in triathletes may seem plausible and thus, may enable this exercise to be performed without much scrutiny.

So…JUMP AWAY!

Photo source

No related posts.

Related posts brought to you by Yet Another Related Posts Plugin.

Scientific knowledge expands daily. This article was published in 2008. I started this blog 3 days ago…THEREFORE…the information you are about to read MAY contain concepts that are obsolete…READER DISCRETION IS ADVISED!

The following is a summary of the IOC current concepts statement published in the British Journal of Sports Medicine last year. Contained within this summary are the general principles that were established based on decades of research pertaining to ACL injuries in female athletes.  Since the amount of potential factors associated with injury are plentiful, this review is limited to only those concepts with conclusive evidence.

Epidemiology

• As a whole, ACL injuries most commonly result from non-contact mechanisms
• Although the rates of ACL injury in men and women are similar in professional sports, younger female athletes are at higher risk (than aged- and sport-matched males)
• Along with men’s spring football, women’s gymnastics, soccer, and basketball have the highest injury rates per 1000/athlete exposures.
• Consistent with most sports, injury rates are higher during competition

Risk Factors

• There is an association between intercondylar notch width and risk of ACL injury. Females generally have smaller notches than males and therefore, likely a smaller ACL. It has been suggested that these ACLs may have lower linear stiffness, fail earlier in elongation, absorb less energy, and fail with lower loads.
• The relationships among the presence of sex hormones within the ACL and oral contraceptives with ACL injury risk are still inconclusive.
• Women appear to be at greater risk of ACL injury during the pre-ovulatory phase.

Mechanism of Non-Contact Injury

• Injuries most often occur when landing from a jump, cutting, or deceleration.
• Kinematic analyses have revealed that women land with less knee flexion than men. Women also maintain higher knee extension and valgus during stance phases of running and cutting. Finally, women also display higher quadriceps EMG activity during max loading. Therefore, a straighter knee and higher quadriceps activation likely contribute to the injury mechanism. Other components include anterior translation, dynamic valgus in near extension, increased trunk motion, and a high load placed on the leg or foot that is away from the body’s COM.

Evaluation

• Key components of diagnosis include: sudden knee pain during high intensity activity, inability to resume play, “popping” sensation, haemarthrosis.
• The course of ACL injury classifies the injured into copers, adaptors, and non-copers.
• ACL reconstruction does not warrant surgical management of the injured MCL.
• The meniscus is associated in approximately 50% of ACL injuries. Note: Mike Reinold recently posted an excellent blog (by D. Lorenz) on meniscal testing here.
• A thorough examination searches for articular cartilage, ligamentous, and bony/bone marrow lesions.
• The pivot shift test is best for ruling in ACL injury. The Lachman test is best for ruling out ACL injury. (It is also the most accurate).
• Patient-administered questionnaires should be used as an outcome measure and quantified scores should be kept separate from categorical variables (good/excellent).
• While the incidence of injury in girls increases at puberty, there is a potential risk of growth disturbances with prepubescent operative management.

Rehabilitation

• Although the restoration of full knee extension is important in initial stages of rehab, ROM should be compared with the unaffected knee to determine normal ranges (hyperextension may be the norm in some patients).
• OKC training should be introduced and progressed cautiously, commencing between 90 and 40 degrees.
• CKC exercises recommended at the commencement of rehab. Early weight bearing and mobilzation are safe.
• A minimum of 3-4 functional performance tests should be used for evaluation.
• Return to play should be goal-based (not time-based)

Prevention

• Most prevention programs utilize neuromuscular and proprioceptive training to alter the dynamic loads placed on the tibiofemoral joint
• Henning was the pioneer in neuromuscular training for ACL injury prevention (just thought I’d add that in, dude deserves his props!)
• Program intervention generally takes a minimum of 4-8 weeks in order to impart its desired effect.
• Programs should be implemented as early as possible (age) and those that use minimal equipment are generally more successful
• In jumping sports, proper landing involves softly landing on the forefoot, rolling back to the rearfoot, two-feet landing, and knee and hip flexion engagement.
• In cutting sports, dynamic valgus should be avoided as the “knee over toe” position should be emphasized.
• Programs should be incorporated as a regular warm-up, should also include strength, power, plyometric, and agility exercises
• The drop vertical jump test is a good way to identify those at risk.

There you have it. My generalized summary of the IOC current concepts statement. Since published research on ACL injuries literally come out daily, please be reminded that some of the above concepts may have been updated.

No related posts.

Related posts brought to you by Yet Another Related Posts Plugin.