Biomechanical measures of short-term maximal cycling on an ergometer: a test-retest study.

An understanding of test-retest reliability is important for biomechanists, such as when assessing the longitudinal effect of training or equipment interventions. Our aim was to quantify the test-retest reliability of biomechanical variables measured during short-term maximal cycling. Fourteen track sprint cyclists performed 3 × 4 s seated sprints at 135 rpm on an isokinetic ergometer, repeating the session 7.6 ± 2.5 days later. Joint moments were calculated via inverse dynamics, using pedal forces and limb kinematics. EMG activity was measured for 9 lower limb muscles. Reliability was explored by quantifying systematic and random differences within- and between-session. Within-session reliability was better than between-sessions reliability. The test-retest reliability level was typically moderate to excellent for the biomechanical variables that describe maximal cycling. However, some variables, such as peak knee flexion moment and maximum hip joint power, demonstrated lower reliability, indicating that care needs to be taken when using these variables to evaluate biomechanical changes. Although measurement error (instrumentation error, anatomical marker misplacement, soft tissue artefacts) can explain some of our reliability observations, we speculate that biological variability may also be a contributor to the lower repeatability observed in several variables including ineffective crank force, ankle kinematics and hamstring muscles' activation patterns.

Quantifying the hip-ankle synergy in short-term maximal cycling.

Simulation studies have demonstrated that the hip and ankle joints form a task-specific synergy during the downstroke in maximal cycling to enable the power produced by the hip extensor muscles to be transferred to the crank. The existence of the hip-ankle synergy has not been investigated experimentally. Therefore, we sought to apply a modified vector coding technique to quantify the strength of the hip-ankle moment synergy in the downstroke during short-term maximal cycling at a pedalling rate of 135 rpm. Twelve track sprint cyclists performed 3 × 4 s seated sprints at 135 rpm, interspersed with 2 × 4 s seated sprints at 60 rpm on an isokinetic ergometer. Data from the 60 rpm sprints were not analysed in this study. Joint moments were calculated via inverse dynamics, using pedal forces and limb kinematics. The hip-ankle moment synergy was quantified using a modified vector coding method. Results showed, for 28.8% of the downstroke the hip and ankle moments were in-phase, demonstrating the hip and ankle joints tend to work in synergy in the downstroke, providing some support findings from simulation studies of cycling. At a pedalling rate of 135 rpm the hip-phase was most frequent (42.5%) significantly differing from the in- (P = 0.044), anti- (P < 0.001), and ankle-phases (P = 0.004), demonstrating hip-dominant action. We believe this method shows promise to answer research questions on the relative strength of the hip-ankle synergy between different cycling conditions (e.g., power output and pedalling rates).

A multi-site prospective, observational study of physiotherapist independent prescribing activity across musculoskeletal clinics in the United Kingdom.

OBJECTIVE: To establish how advanced practice physiotherapists in the UK working in the musculoskeletal specialty are utilising their independent non-medical prescribing skills. DESIGN: Multi-site, prospective, descriptive observational study. Ethics reference No: ERN_19-0994). METHOD: The study was conducted by seven advanced practitioners, across seven clinical sites representative of advanced musculoskeletal practice in the UK, between 1st October 2019-March 31, 2020. Advanced physiotherapy practitioner independent prescribers working in a variety of musculoskeletal specialty areas collected data across 5 contexts of musculoskeletal clinical service: first contact practice, primary care, community triage, secondary care orthopaedics, secondary care rheumatology and private practice. Quantitative data were analysed descriptively with qualitative data analysed/synthesised via thematic analysis. RESULTS: Prescribing activity data for n = 2470 patients were collected. Prescribing activity was highest for the treatment of nociceptive pain (51.3%) and inflammation (39.6%). Most prescribing activity occurred in the first 2-6 weeks (34.1%) following onset of condition. Medicines optimisation accounted for most of prescribing activity (18.1%), followed by over-the-counter medication recommendation (15.5%). De-prescribing accounted for 10.8% of all prescribing activity recorded. Qualitative data were synthesised into 4 themes: multimodal physiotherapeutic approach, joint decision making and patient choice, working with complexity, and legal and regulatory restriction. CONCLUSIONS: Physiotherapist independent prescribing was used within all health sectors in conjunction with advanced skills in musculoskeletal physiotherapy as part of a multimodal physiotherapeutic approach. Prescribing activity was dictated by the clinicians' clinical reasoning and use of joint decision-making. Prescribing activity for acute back and neuropathic radicular pain was limited secondary to recent reclassification of gabapentin and pregabalin.

Effects of strength training on the biomechanics and coordination of short-term maximal cycling.

The aim was to investigate the effects of a gym-based strength training intervention on biomechanics and intermuscular coordination patterns during short-term maximal cycling. Twelve track sprint cyclists performed 3 × 4 s seated sprints at 135 rpm, interspersed with 2 × 4 s seated sprints at 60 rpm on an isokinetic ergometer, repeating the session 11.6 ± 1.4 weeks later following a training programme that included two gym-based strength training sessions per week. Joint moments were calculated via inverse dynamics, using pedal forces and limb kinematics. EMG activity was measured for 9 lower limb muscles. Track cyclists 'leg strength" increased (7.6 ± 11.9 kg, P = 0.050 and ES = 0.26) following the strength training intervention. This was accompanied by a significant increase in crank power over a complete revolution for sprints at 135 rpm (26.5 ± 36.2 W, P = 0.028 and ES = 0.29). The increase in leg strength and average crank power was associated with a change in biceps femoris muscle activity, indicating that the riders successfully adapted their intermuscular coordination patterns to accommodate the changes in personal constraints to increase crank power.

The systemic immunosuppressive effects of peripheral corticosteroid injections: A narrative review of the evidence in the context of COVID-19.

INTRODUCTION: Injected glucocorticoid's (corticosteroids) are commonly used in musculoskeletal practice. The current global COVID-19 pandemic has increased attention on the potential for locally injected corticosteroids to exert a systemic immunosuppressive effect and the implications this may have in relation to COVID-19 infection and vaccination. AIM: This narrative review summarises the evidence regarding the potential systemic immunosuppressive effects of peripheral corticosteroid injections in relation to the ongoing COVID-19 pandemic. METHOD: A narrative review was selected to allow inclusion of evidence related to a diverse range of topics relevant to this subject in order to provide the most comprehensive and clinically relevant guidance for clinicians. RESULTS/DISCUSSION: Current evidence demonstrates that cytotoxic, phagocytic and antigen presenting cells involved in both the innate and adaptive immune responses are suppressed for 48 h post-injection and messenger cytokines that are integral to immune function are suppressed for over 96 h post-injection. This potentially reduces an individual's ability to prevent viral infection, limit early viral replication, and delays activation of adaptive immune mechanisms (T and B lymphocytes) and subsequent viral clearance and elimination. The hypothalamic-pituitary-adrenal (HPA) axis can be suppressed for 2-4 weeks or longer following peripheral corticosteroid injections. The role of the HPA axis in immune function is not fully understood, however this could potentially indicate longer lasting immunosuppression. CONCLUSIONS: This review found evidence of suppression of immune cell numbers for the first 48 h post-injection, cytokines for over 96 h post-injection and HPA axis suppression lasting for 2-4 weeks or longer. There is currently no evidence that these physiological changes translate into a clinically meaningful increased risk of COVID-19 infection or related morbidity or mortality, but there is also no persuasive evidence that they do not. This review discusses the implications of the current evidence in relation to shared decision making, informed consent, risk management and COVID-19 vaccination to provide clinicians with a pragmatic guide to help navigate the current uncertainty regarding the potential immunosuppressive effects of peripheral corticosteroid injections.

Mechanical and morphological determinants of peak power output in elite cyclists.

Mechanical peak power output (PPO) is a determinant of performance in sprint cycling. The purpose of this study was to examine the relationship between PPO and putative physiological determinants of PPO in elite cyclists, and to compare sprint performance between elite sprint and endurance cyclists. Thirty-five elite cyclists (18 endurance; 17 sprint) performed duplicate sprint cycling laboratory tests to establish PPO and its mechanical components. Quadriceps femoris (QVOL ) and hamstring muscle volume (HAMVOL ) were assessed with MRI, vastus lateralis pennation angle (PθVL ) and fascicle length (FLVL ) were determined with ultrasound imaging, and neuromuscular activation of three muscles was assessed using EMG at PPO during sprint cycling. For the whole cohort, there was a wide variability in PPO (range 775-2025 W) with very large, positive, bivariate relationships between PPO and QVOL (r = .87), HAMVOL (r = .71), and PθVL (r = .81). Step-wise multiple regression analysis revealed that 87% of the variability in PPO between cyclists was explained by two variables QVOL (76%) and PθVL (11%). The sprint cyclists had greater PPO (+61%; P < .001 vs endurance), larger QVOL (P < .001), and BFVOL (P < .001) as well as more pennate vastus lateralis muscles (P < .001). These findings emphasize the importance of quadriceps muscle morphology for sprint cycling events.

Isovelocity vs. Isoinertial Sprint Cycling Tests for Power- and Torque-cadence Relationships.

Sprint cycling performance is heavily dependent on mechanical peak power output (PPO) and the underlying power- and torque-cadence relationships. Other key indices of these relationships include maximum torque (TMAX), cadence (CMAX) and optimal cadence (COPT). Two common methods are used in the laboratory to ascertain PPO: isovelocity and isoinertial. Little research has been carried out to compare the magnitude and reliability of these performance measures with these two common sprint cycling assessments. The aim of this study was to compare the magnitude and reliability of PPO, TMAX, CMAX and COPT measured with isovelocity and isoinertial sprint cycling methods. Two experimental sessions required 20 trained cyclists to perform isoinertial sprints and then isovelocity sprints. For each method, power-cadence and torque-cadence relationships were established, and PPO and COPT were interpolated and TMAX and CMAX were extrapolated. The isoinertial method produced significantly higher PPO (p<0.001) and TMAX (p<0.001) than the isovelocity method. However, the isovelocity method produced significantly higher COPT (p<0.001) and CMAX (p=0.002). Both sprint cycling tests showed high levels of between-session reliability (isoinertial 2.9-4.4%; isovelocity 2.7-4.0%). Functional measures of isovelocity and isoinertial sprint cycling tests were highly reliable but should not be used interchangably.

Reliability of traditional and task specific reference tasks to assess peak muscle activation during two different sprint cycling tests.

Neuromuscular activation is considered an important determinant sprint cycling performance but requires reliable EMG amplitude measurements to facilitate sensitive assessments. The reliability of EMG measurements during sprint cycling may depend on the sprint cycling test undertaken (isovelocity or isoinertial accelerating), the reference tasks used for normalisation (isometric MVCs of a series of single muscle groups [ISO-SINGJT] or isometric cycling MVCs [ISO-CYC]), and the efficacy of the normalisation. This study aimed to compare the magnitude and between-session reliability of peak muscle activation (peak rmsEMG) during: isovelocity and isoinerital sprint cycling tests; ISO-SINGJT and ISO-CYC reference tasks; and absolute and normalised EMG during the sprint cycling tests. EMG amplitude was measured over six major muscle groups on both legs and all measurements were made over two sessions in a randomised counterbalanced design. Peak rmsEMG was assessed during both ISO-SINGJT and ISO-CYC MVCs and then during mechanical peak power output (PPO) during isovelocity (120 RPM) and isoinerital acceleration (0 to >150 RPM) sprint tests. Absolute peak rmsEMG and for the sprint tests normalised EMG values were determined, and coefficient of variation and intra-class correlation coefficients used to assess reliability. Peak rmsEMG at PPO during both sprint cycling tests was similar for the six muscle groups measured. Peak rmsEMG was higher during ISO-SINGJT than ISO-CYC for for 3 of the 6 muscle groups, but all muscle groups exhibited similar reliability for both reference tasks. Neither reference task improved the between-session reliability for either sprint test. This data highlights reservations in the use of isometric reference tasks to ascertain changes in peak muscle activation over time in during sprint cycling assessments.

Reliability and validity of depth camera 3D scanning to determine thigh volume.

Gross thigh volume is a key anthropometric variable to predict sport performance and health. Currently, it is either estimated by using the frustum method, which is prone to high inter-and intra-observer error, or using medical imaging, which is expensive and time consuming. Depth camera 3D-imaging systems offer a cheap alternative to measure thigh volume but no between-session reliability or comparison to medical imaging has been made. This experiment established between-session reliability and examined agreement with magnetic resonance imaging (MRI). Forty-eight male cyclists had their thigh volume measured by the depth camera system on two occasions to establish between-session reliability. A subset of 32 participants also had lower body MRIs, through which agreement between the depth camera system and MRI was established. The results showed low between-session variability (CV = 1.7%; Absolute Typical Error = 112 cm3) when measuring thigh volume using the depth camera system. The depth camera systematically measured gross thigh volume 32.6cm3 lower than MRI. These results suggest that depth camera 3D-imaging systems are reliable tools for measuring thigh volume and show good agreement with MRI scanners, providing a cheap and time-saving alternative to medical imaging analysis.

A service evaluation and improvement project: a three year systematic audit cycle of the physiotherapy treatment for Lateral Epicondylalgia.

OBJECTIVES: To improve outcomes of physiotherapy treatment for patients with Lateral Epicondylalgia. DESIGN: A systematic audit and quality improvement project over three phases, each of one year duration. SETTING: Salford Royal NHS Foundation Trust Teaching Hospital Musculoskeletal Physiotherapy out-patients department. PARTICIPANTS: n=182. INTERVENTIONS: Phase one - individual discretion; Phase two - strengthening as a core treatment however individual discretion regarding prescription and implementation; Phase three - standardised protocol using high load isometric exercise, progressing on to slow combined concentric & eccentric strengthening. MAIN OUTCOME MEASURES: Global Rating of Change Scale, Pain-free grip strength, Patient Rated Tennis Elbow Evaluation, Tampa Scale of Kinesophobia-11. RESULTS: Phase three demonstrated a reduction in the average number of treatments by 42% whilst improving the number of responders to treatment by 8% compared to phase one. Complete cessation of non-evidence based treatments was also observed by phase three. CONCLUSIONS: Strengthening should be a core treatment for LE. Load setting needs to be sufficient. In phase three of the audit a standardised tendon loading programme using patient specific high load isometric exercises into discomfort/pain demonstrated a higher percentage of responders compared to previous phases.

Relation between Peak Power Output in Sprint Cycling and Maximum Voluntary Isometric Torque Production.

From a cycling paradigm, little has been done to understand the relationships between maximal isometric strength of different single joint lower body muscle groups and their relation with, and ability to predict PPO and how they compare to an isometric cycling specific task. The aim of this study was to establish relationships between maximal voluntary torque production from isometric single-joint and cycling specific tasks and assess their ability to predict PPO. Twenty male trained cyclists participated in this study. Peak torque was measured by performing maximum voluntary contractions (MVC) of knee extensors, knee flexors, dorsi flexors and hip extensors whilst instrumented cranks measured isometric peak torque from MVC when participants were in their cycling specific position (ISOCYC). A stepwise regression showed that peak torque of the knee extensors was the only significant predictor of PPO when using SJD and accounted for 47% of the variance. However, when compared to ISOCYC, the only significant predictor of PPO was ISOCYC, which accounted for 77% of the variance. This suggests that peak torque of the knee extensors was the best single-joint predictor of PPO in sprint cycling. Furthermore, a stronger prediction can be made from a task specific isometric task.

Healthy competition: A qualitative study investigating persuasive technologies and the gamification of cycling.

Changing socio-technical practices occurring within cycling are leading the pursuit, and its participants, to become ever more embedded into the networked digital world. GPS enabled mobile-technologies have introduced a new element of competition into recreational riding, whether on the road, competing over timed virtual segments, or online dissecting and comparing the data that has been logged and shared via dedicated ride-logging applications. In order to understand these technologies qualitative study using reflective diaries and semi-structured interviews has been conducted with experienced club cyclists who had fully experienced the effects of their arrival. These riders claim that the applications influence their route choice and motivate them to cycle more frequently, and at a greater intensity although the engagement changes over time. This paper explores how this increased motivation to exercise and compete is instigated, manifested and maintained in the everyday practices of cyclists, as well as the negative consequences of gamification.

Conservative treatments for greater trochanteric pain syndrome: a systematic review.

BACKGROUND: Greater trochanteric pain syndrome (GTPS) can have a significant effect on quality of life. AIM: To evaluate the conservative treatments for GTPS. DESIGN: This systematic review assessed risk of bias using the Cochrane Risk of Bias Tool and Cochrane Risk of Bias Tool for non-randomised studies of interventions. DATA SOURCES: On 13 January 2016, a comprehensive search was conducted, with no limit on year of publication for relevant studies in the MEDLINE, CINAHL, AMED and EMBASE databases. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: English language randomised controlled trials, case-control or cohort studies reporting outcome data for conservative treatments for adults having a diagnosis of GTPS, or trochanteric bursitis, were included. RESULTS: 8 studies (n=696) were eligible for inclusion in the review; corticosteroid injections (CSI) (n=6), shockwave therapy (n=2), home training (n=1) and orthotics (n=1). Based on pain, CSI demonstrated superior outcomes for up to 3 months compared with home training, radial shockwave therapy (RSWT) and usual care, in 4 studies demonstrating either a low or moderate risk of bias. Fluoroscopy-guided injections failed to show additional benefit. RSWT and home training had limited evidence. No conclusions can be drawn regarding the use of orthotics due to the serious risk of bias and methodological flaws within that study. CONCLUSIONS: This review demonstrates a paucity of high-quality research for the conservative treatments of GTPS. The risk of bias was low in only one study, demonstrating no additional benefit with fluoroscopically guided injections. Risk of bias in all remaining studies was varied. Standardisation of diagnostic criteria and outcome measures is essential to enable more powerful analysis.

Effects of Pedal Speed and Crank Length on Pedaling Mechanics during Submaximal Cycling.

UNLABELLED: During submaximal cycling, the neuromuscular system has the freedom to select different intermuscular coordination strategies. From both a basic science and an applied perspective, it is important to understand how the central nervous system adjusts pedaling mechanics in response to changes in pedaling conditions. PURPOSE: To determine the effect of changes in pedal speed (a marker of muscle shortening velocity) and crank length (a marker of muscle length) on pedaling mechanics during submaximal cycling. METHODS: Fifteen trained cyclists performed submaximal isokinetic cycling trials (90 rpm, 240 W) using pedal speeds of 1.41 to 1.61 m·s(-1) and crank lengths of 150 to 190 mm. Joint powers were calculated using inverse dynamics. RESULTS: Increases in pedal speed and crank length caused large increases knee and hip angular excursions and velocities (P < 0.05), whereas ankle angular kinematics stayed relatively constant (P > 0.05). Joint moments and joint powers were less affected by changes in the independent variables, but some interesting effects and trends were observed. Most noteworthy, knee extension moments and powers tended to decrease, whereas hip extension power tended to increase with an increase in crank length. CONCLUSIONS: The distribution of joint moments and powers is largely maintained across a range of pedaling conditions. The crank length induced differences in knee extension moments, and powers may represent a trade-off between the central nervous system's attempts to simultaneously minimize muscle metabolic and mechanical stresses. These results increase our understanding of the neural and mechanical mechanisms underlying multi-joint task performance, and they have practical relevance to coaches, athletes, and clinicians.

Joint-specific power production during submaximal and maximal cycling.

UNLABELLED: Separate authors have reported that knee extension dominates power production during submaximal cycling (SUB(cyc)) and hip extension is the dominant action during maximal cycling (MAX(cyc)). Changes in joint-specific powers across broad ranges of net cycling powers (P(net)) within one group of cyclists have not been reported. PURPOSE: Our purpose was to determine the extent to which ankle, knee, and hip joint actions produced power across a range of P(net) . We hypothesized that relative knee extension power would decrease and relative knee flexion and hip extension powers would increase as P(net) increased. METHODS: Eleven cyclists performed SUB(cyc) (250, 400, 550, 700, and 850 W) and MAX(cyc) trials at 90 rpm. Joint-specific powers were calculated and averaged over complete pedal revolutions and over extension and flexion phases. Portions of the cycle spent in extension (duty cycle) were determined for the whole leg and ankle, knee, and hip joints. Relationships of relative joint-specific powers with P(net) were assessed with linear regression analyses. RESULTS: Absolute ankle, knee, and hip joint-specific powers increased as P(net) increased. Relative knee extension power decreased (r(2) = 0.88, P = 0.01) and knee flexion power increased (r(2) = 0.98, P < 0.001) as P(net) increased. Relative hip extension power was constant across all P(net) . Whole-leg and ankle, knee, and hip joint duty cycle values were greater for MAX(cyc) than for SUB(cyc). CONCLUSIONS: Our data demonstrate that 1) absolute ankle, knee, and hip joint-specific powers substantially increase as a function of increased P(net) , 2) hip extension was the dominant power-producing action during SUB(cyc) and MAX(cyc), 3) knee flexion power becomes relatively more important during high-intensity cycling, and 4) increased duty cycle values represent an important strategy to increase maximum power.

Effect of crank length on joint-specific power during maximal cycling.

UNLABELLED: Previous investigators have suggested that crank length has little effect on overall short-term maximal cycling power once the effects of pedal speed and pedaling rate are accounted for. Although overall maximal power may be unaffected by crank length, it is possible that similar overall power might be produced with different combinations of joint-specific powers. Knowing the effects of crank length on joint-specific power production during maximal cycling may have practical implications with respect to avoiding or delaying fatigue during high-intensity exercise. PURPOSE: The purpose of this study was to determine the effect of changes in crank length on joint-specific powers during short-term maximal cycling. METHODS: Fifteen trained cyclists performed maximal isokinetic cycling trials using crank lengths of 150, 165, 170, 175, and 190 mm. At each crank length, participants performed maximal trials at pedaling rates optimized for maximum power and at a constant pedaling rate of 120 rpm. Using pedal forces and limb kinematics, joint-specific powers were calculated via inverse dynamics and normalized to overall pedal power. RESULTS: ANOVAs revealed that crank length had no significant effect on relative joint-specific powers at the hip, knee, or ankle joints (P > 0.05) when pedaling rate was optimized. When pedaling rate was constant, crank length had a small but significant effect on hip and knee joint power (150 vs 190 mm only) (P < 0.05). CONCLUSIONS: These data demonstrate that crank length does not affect relative joint-specific power once the effects of pedaling rate and pedal speed are accounted for. Our results thereby substantiate previous findings that crank length per se is not an important determinant of maximum cycling power production.