The 3D kinematics of the single leg flat and decline squat

Background: Pre-participation screening is commonly used to measure and assess potential intrinsic injury risk. The single leg squat is one such clinical screening measure used to assess lumbopelvic stability and associated intrinsic injury risk. With the addition of a decline board, the single leg decline squat (SLDS) has been shown to reduce ankle dorsiflexion restrictions and allowed greater sagittal plane movement of the hip and knee. On this basis, the SLDS has been employed in the Cricket Australia physiotherapy screening protocols as a measure of lumbopelvic control in the place of the more traditional single leg flat squat (SLFS). Previous research has failed to demonstrate which squatting technique allows for a more comprehensive assessment of lumbopelvic stability. Tenuous links are drawn between kinematics and hip strength measures within the literature for the SLS. Formal evaluation of subjective screening methods has also been suggested within the literature. Purpose: This study had several focal points namely 1) to compare the kinematic differences between the two single leg squatting conditions, primarily the five key kinematic variables fundamental to subjectively assess lumbopelvic stability; 2) determine the effect of ankle dorsiflexion range of motion has on squat kinematics in the two squat techniques; 3) examine the association between key kinematics and subjective physiotherapists’ assessment; and finally 4) explore the association between key kinematics and hip strength. Methods: Nineteen (n=19) subjects performed five SLDS and five SLFS on each leg while being filmed by an 8 camera motion analysis system. Four hip strength measures (internal/external rotation and abd/adduction) and ankle dorsiflexion range of motion were measured using a hand held dynamometer and a goniometer respectively on 16 of these subjects. The same 16 participants were subjectively assessed by an experienced physiotherapist for lumbopelvic stability. Paired samples t-tests were performed on the five predetermined kinematic variables to assess the differences between squat conditions. A Bonferroni correction for multiple comparisons was used which adjusted the significance value to p = 0.005 for the paired t-tests. Linear regressions were used to assess the relationship between kinematics, ankle range of motion and hip strength measures. Bivariate correlations between hip strength measures and kinematics and pelvic obliquity were employed to investigate any possible relationships. Results: 1) Significant kinematic differences between squats were observed in dominant (D) and non-dominant (ND) end of range hip external rotation (ND p = <0.001; D p = 0.004) and hip adduction kinematics (ND p = <0.001; D p = <0.001). With the mean angle, only the non-dominant leg observed significant differences in hip adduction (p = 0.001) and hip external rotation (p = <0.001); 2) Significant linear relationships were observed between clinical measures of ankle dorsiflexion and sagittal plane kinematic namely SLFS dominant ankle (p = 0.006; R2 = .429), SLFS non-dominant knee (p = 0.015; R2 = .352) and SLFS non-dominant ankle (p = 0.027; R2 = .305) kinematics. Only the dominant ankle (p = 0.020; R2 = .331) was found to have a relationship with the decline squat. 3) Strength measures had tenuous associations with the subjective assessments of lumbopelvic stability with no significant relationships being observed. 4) For the non-dominant leg, external rotation strength and abduction strength were found to be significantly correlated with hip rotation kinematics (Newtons r = 0.458 p = 0.049; Normalised for bodyweight: r = 0.469; p = 0.043) and pelvic obliquity (normalised for bodyweight: r = 0.498 p = 0.030) respectively for the SLFS only. No significant relationships were observed in the dominant leg for either squat condition. Some elements of the hip strength screening protocols had linear relationships with kinematics of the lower limb, particularly the sagittal plane movements of the knee and ankle. Strength measures had tenuous associations with the subjective assessments of lumbopelvic stability with no significant relationships being observed; Discussion: The key finding of this study illustrated that kinematic differences can occur at the hip without significant kinematic differences at the knee as a result of the introduction of a decline board. Further observations reinforce the role of limited ankle dorsiflexion range of motion on sagittal plane movement of the hip and knee and in turn multiplanar kinematics of the lower limb. The kinematic differences between conditions have clinical implications for screening protocols that employ frontal plane movement of the knee as a guide for femoral adduction and rotation. Subjects who returned stronger hip strength measurements also appeared to squat deeper as characterised by differences in sagittal plane kinematics of the knee and ankle. Despite the aforementioned findings, the relationship between hip strength and lower limb kinematics remains largely tenuous in the assessment of the lumbopelvic stability using the SLS. The association between kinematics and the subjective measures of lumbopelvic stability also remain tenuous between and within SLS screening protocols. More functional measures of hip strength are needed to further investigate these relationships. Conclusion: The type of SLS (flat or decline) should be taken into account when screening for lumbopelvic stability. Changes to lower limb kinematics, especially around the hip and pelvis, were observed with the introduction of a decline board despite no difference in frontal plane knee movements. Differences in passive ankle dorsiflexion range of motion yielded variations in knee and ankle kinematics during a self-selected single leg squatting task. Clinical implications of removing posterior ankle restraints and using the knee as a guide to illustrate changes at the hip may result in inaccurate screening of lumbopelvic stability. The relationship between sagittal plane lower limb kinematics and hip strength may illustrate that self-selected squat depth may presumably be a useful predictor of the lumbopelvic stability. Further research in this area is required.

Eccentric decline squat protocol offers superior results at 12 months compared with traditional eccentric protocol for patellar tendinopathy in volleyball players

Background: Conservative treatment of patellar tendinopathy has been minimally investigated. Effective validated treatment protocols are required.

Objectives: To investigate the immediate (12 weeks) and long term (12 months) efficacy of two eccentric exercise programmes for the treatment of patellar tendinopathy.

Methods: This was a prospective randomised controlled trial of 17 elite volleyball players with clinically diagnosed and imaging confirmed patellar tendinopathy. Participants were randomly assigned to one of two treatment groups: a decline group and a step group. The decline group were required to perform single leg squats on a 25° decline board, exercising into tendon pain and progressing their exercises with load. The step group performed single leg squats on a 10 cm step, exercising without tendon pain and progressing their exercises with speed then load. All participants completed a 12 week intervention programme during their preseason. Outcome measures used were the Victorian Institute of Sport Assessment (VISA) score for knee function and 100 mm visual analogue scale (VAS) for tendon pain with activity. Measures were taken throughout the intervention period and at 12 months.

Results: Both groups had improved significantly from baseline at 12 weeks and 12 months. Analysis of the likelihood of a 20 point improvement in VISA score at 12 months revealed a greater likelihood of clinical improvements in the decline group than the step group. VAS scores at 12 months did not differ between the groups.

Conclusions: Both exercise protocols improved pain and sporting function in volleyball players over 12 months. This study indicates that the decline squat protocol offers greater clinical gains during a rehabilitation programme for patellar tendinopathy in athletes who continue to train and play with pain.

A pilot study of the eccentric decline squat in the management of painful chronic patellar tendinopathy

Objectives: This non-randomised pilot study investigated the effect of eccentric quadriceps training on 17 patients (22 tendons) with painful chronic patellar tendinopathy.

Methods: Two different eccentric exercise regimens were used by subjects with a long duration of pain with activity (more than six months). (a) Nine consecutive patients (10 tendons; eight men, one woman; mean age 22 years) performed eccentric exercise with the ankle joint in a standard (foot flat) position. (b) Eight patients (12 tendons; five men, three women; mean age 28 years) performed eccentric training standing on a 25° decline board, designed to increase load on the knee extensor mechanism. The eccentric training was performed twice daily, with three sets of 15 repetitions, for 12 weeks. Primary outcome measures were (a) 100 mm visual analogue scale (VAS), where the subject recorded the amount of pain during activity, and (b) return to previous activity. Follow up was at 12 weeks, with a further limited follow up at 15 months.

Results: Good clinical results were obtained in the group who trained on the decline board, with six patients (nine tendons) returning to sport and showing a significantly reduced amount of pain over the 12 week period. Mean VAS scores fell from 74.2 to 28.5 (p = 0.004). At 15 months, four patients (five tendons) reported satisfactory results (mean VAS 26.2). In the standard squat group the results were poor, with only one athlete returning to previous activity. Mean VAS scores in this group were 79.0 at baseline and 72.3 at 12 weeks (p = 0.144).

Conclusion: In a small group of patients with patellar tendinopathy, eccentric squats on a decline board produced encouraging results in terms of pain reduction and return to function in the short term. Eccentric exercise using standard single leg squats in a similar sized group appeared to be a less effective form of rehabilitation in reducing pain and returning subjects to previous levels of activity.

Discriminative ability of functional loading tests for adolescent jumper's knee

Objective. To investigate the reliability and validity of five squat-based loading tests that are clinically appropriate for jumper's knee. The loading tests were step up, double leg squat, double leg squat on a 25-degree decline (decline squat), single leg decline squat, and decline hop. Design. Cross-sectional controlled cohort. Subjects without knee pain comprised controls, those with extensor tendon pain comprised the jumper's knee group. Setting. Institutional athlete study group in Australia Participants. Fifty-six elite adolescent basketball players participated in this study, thirteen comprised the jumper's knee group, fifteen athletes formed a control group. Intervention. Each subject performed each loading test for baseline and reliability data on the first testing day. Subjects then performed three days of intensive (6 h daily) basketball training, after which each loading test was reexamined. Main outcome measures. Eleven point interval scale for pain. Results. The tests that best detected a change in pain due to intensive workload were the single leg decline squat and single leg decline hop. This study found that decline tests have better discriminative ability than the standard squat to detect change in jumper's knee pain due to intensive training. The typical error for these tests ranged from 0.3 to 0.5, however, caution should be exercised in the interpretation of these reliability figures due to relatively low scores. Conclusions. The single leg decline squat is recommended in the physical assessment of adolescent jumper's knee. The decline squat was selected as the best clinical test over the decline hop because it was easier to standardise performance.

Neovascularization and pain in abnormal patellar tendons of active jumping athletes

Objective: The aim of this study was to investigate tendon pain in abnormal patellar tendons with and without neovascularization.

Study design: Comparative design.

Setting: Multidisciplinary tendon study group at a competitive volleyball venue.

Participants: One hundred eleven volleyball players volunteered to participate in the study.

Main Outcome Measures: Subjects' patellar tendons were imaged with ultrasound, with and without Doppler. Tendons that were imaging abnormal were categorized according the presence of tendon neovascularization. Subjects completed 3 pain scales that examined function (Victorian Institute of Sport Assessment score, 100-point maximum), pain with tendon load (decline squat, visual analogue scale, 100-mm maximum), and maximum pain for the previous week (visual analogue scale, 100-mm maximum). A 1-tailed Mann-Whitney U test compared pain scores in abnormal tendons without neovascularization to abnormal tendons with neovascularization.

Results: Functional scores were lower (Victorian Institute of Sport score, median, 78; P = 0.045) and pain scores under tendon load were greater (decline squat pain, median, 19; P = 0.048) in subjects with abnormal tendons with neovascularization than subjects with abnormal tendons without neovascularization (Victorian Institute of Sport Assessment score, median, 87; decline squat pain, median, 0).

Conclusions: This study indicates that the presence of neovascularization in abnormal patellar tendons is associated with greater tendon pain compared with abnormal tendons without neovascularization in active jumping athletes.

Patellar tendons with normal imaging and pain: change in imaging and pain status over volleyball season

Objective: Patellar tendon injury commonly presents as abnormal imaging with pain or abnormal imaging without pain. Normal imaging with pain has also been reported clinically, but little is known about the behavior of these tendons over time. This study investigated the behavior of tendons with normal imaging and pain over a volleyball season.

Design: Prospective study.

Setting: Institutional.

Participants: One hundred and one male and female volleyball players.

Main outcome measurements: At the beginning and end of the season ultrasound determined imaging status and the single leg decline squat test determined pain. The imaging and pain status at follow-up of tendons with normal imaging and pain at baseline was reported and contrasted to the imaging and pain status of the other patellar tendon injuries.

Results: Tendons with normal imaging and pain [relative risk (RR) 15.1], abnormal imaging without pain (RR 14.6), and abnormal imaging with pain (RR 51.5) had a greater risk of having abnormal imaging with pain at the end of the season when compared with normal tendons (P < 0.01). Among tendons with normal imaging and pain at baseline, 27% had abnormal imaging without pain and 21% contained abnormal imaging with pain at the end of the season.

Conclusions: Patellar tendons with normal imaging and pain at the beginning of a volleyball season are equally as likely to have abnormal imaging and pain at the end of the season as tendons with abnormal imaging without pain. Normal imaging with pain may represent a clinically relevant patellar tendon injury.

Prospective study of change in patellar tendon abnormality on imaging and pain over volleyball season

Objective: Patellar tendon injury, defined by tendon abnormality (TA) on imaging and by pain, is common among volleyball players, but little is known about change in this injury over a volleyball season. Increased activity in the season compared with the off season may result in the development of TA and/or pain. This study investigated the behaviour of TA and pain over a competitive volleyball season.

Methods: Tendon abnormality and pain were measured in 101 volleyball players at the beginning and end of a season. Pain was measured with the single leg decline squat test, which loads the patellar tendon, and TA was detected with ultrasound imaging. Hours of weekly activity were measured and compared during the season and the off season. The proportion of tendons that underwent development and resolution in TA and/or pain over the season was investigated.

Results: Hours of weekly activity was greater during the season than in the off season. Most of the tendons investigated (66.3%) did not undergo a change in TA or pain over the season. Tendon abnormality and/or pain developed in 16.6% of tendons and resolved in 11.2%.

Conclusions: The tendons of volleyball players respond variably to the increased load over the season. Change in TA and pain does not appear to be entirely dependent upon load.

Discriminative ability of functional loading tests for adolescent jumper

Objective: To investigate the reliability and validity of five squat-based loading tests that are clinically appropriate for jumper's knee. The loading tests were step up, double leg squat, double leg squat on a 25-degree decline (decline squat), single leg decline squat, and decline hop. Design: Cross-sectional controlled cohort. Subjects without knee pain comprised controls, those with extensor tendon pain comprised the jumper's knee group. Setting: Institutional athlete study group in Australia. Participants: Fifty-six elite adolescent basketball players participated in this study, thirteen comprised the jumper's knee group, fifteen athletes formed a control group. Intervention: Each subject performed each loading test for baseline and reliability data on the first testing day. Subjects then performed three days of intensive (6 h daily) basketball training, after which each loading test was reexamined. Main outcome measures: Eleven point interval scale for pain. Results: The tests that best detected a change in pain due to intensive workload were the single leg decline squat and single leg decline hop. This study found that decline tests have better discriminative ability than the standard squat to detect change in jumper's knee pain due to intensive training. The typical error for these tests ranged from 0.3 to 0.5, however, caution should be exercised in the interpretation of these reliability figures due to relatively low scores. Conclusions: The single leg decline squat is recommended in the physical assessment of adolescent jumper's knee. The decline squat was selected as the best clinical test over the decline hop because it was easier to standardise performance.

Isometric exercise induces analgesia and reduces inhibition in patellar tendinopathy

BACKGROUND: Few interventions reduce patellar tendinopathy (PT) pain in the short term. Eccentric exercises are painful and have limited effectiveness during the competitive season. Isometric and isotonic muscle contractions may have an immediate effect on PT pain. METHODS: This single-blinded, randomised cross-over study compared immediate and 45 min effects following a bout of isometric and isotonic muscle contractions. Outcome measures were PT pain during the single-leg decline squat (SLDS, 0-10), quadriceps strength on maximal voluntary isometric contraction (MVIC), and measures of corticospinal excitability and inhibition. Data were analysed using a split-plot in time-repeated measures analysis of variance (ANOVA). RESULTS: 6 volleyball players with PT participated. Condition effects were detected with greater pain relief immediately from isometric contractions: isometric contractions reduced SLDS (mean±SD) from 7.0±2.04 to 0.17±0.41, and isotonic contractions reduced SLDS (mean±SD) from 6.33±2.80 to 3.75±3.28 (p<0.001). Isometric contractions released cortical inhibition (ratio mean±SD) from 27.53%±8.30 to 54.95%±5.47, but isotonic contractions had no significant effect on inhibition (pre 30.26±3.89, post 31.92±4.67; p=0.004). Condition by time analysis showed pain reduction was sustained at 45 min postisometric but not isotonic condition (p<0.001). The mean reduction in pain scores postisometric was 6.8/10 compared with 2.6/10 postisotonic. MVIC increased significantly following the isometric condition by 18.7±7.8%, and was significantly higher than baseline (p<0.001) and isotonic condition (p<0.001), and at 45 min (p<0.001). CONCLUSIONS: A single resistance training bout of isometric contractions reduced tendon pain immediately for at least 45 min postintervention and increased MVIC. The reduction in pain was paralleled by a reduction in cortical inhibition, providing insight into potential mechanisms. Isometric contractions can be completed without pain for people with PT. The clinical implications are that isometric muscle contractions may be used to reduce pain in people with PT without a reduction in muscle strength.

Unionization : a necessary strategy to arrest professional decline?

This article examines contemporary social work and why it is under serious threat, ideologically and economically, in a rapidly changing world that no longer highly values its social mandate, methods, and outcomes. Within this hostile environment we investigate the low salaries and high student debt that beginning social workers experience, which might otherwise drive them into unions. Instead, the profession resists unionization, preferring to remain focused on its ideals rather than the disquieting marketplace realities. We then examine the general elements of a hybrid union model that can assist social workers to organize and thus arrest their long-standing professional and fiscal decline.

Older adults, interface experience and cognitive decline

This paper describes an experiment undertaken to investigate intuitive interaction, particularly in older adults. Previous work has shown that intuitive interaction relies on past experience, and has also suggested that older people demonstrate less intuitive uses and slower times when completing set tasks with various devices. Similarly, this experiment showed that past experience with relevant products allowed people to use the interfaces of two different microwaves more quickly and intuitively. It also revealed that certain aspects of cognitive decline related to aging, such as central executive function, have more impact on time, correct uses and intuitive uses than chronological age. Implications of these results are discussed.