Hop Forwarding Research Articles

Acute Talar Cartilage Deformation in Those with and without Chronic Ankle Instability.

This study aimed 1) to determine whether talar cartilage deformation measured via ultrasonography (US) after standing and hopping loading protocols differs between chronic ankle instability (CAI) patients and healthy controls and 2) to determine whether the US measurement of cartilage deformation reflects viscoelasticity between standing and hopping protocols. A total of 30 CAI and 30 controls participated. After a 60-min off-loading period, US images of the talar cartilage were acquired before and after static (2-min single-leg standing) and dynamic (60 single-leg forward hops) loading conditions. We calculated cartilage deformation by assessing the change in average thickness (mm) for overall, medial, and lateral talar cartilage. The independent variables include time (Pre60 and postloading), condition (standing and dynamic loading), and group (CAI and control). A three-way mixed-model repeated-measures ANCOVA and appropriate post hoc tests were used to compare cartilage deformation between the groups after static and dynamic loading. After the static loading condition, those with CAI had greater talar cartilage deformation compared with healthy individuals for overall (-10.87% vs -6.84%, P = 0.032) and medial (-12.98% vs -5.80%, P = 0.006) talar cartilage. Similarly, the CAI group had greater deformation relative to the control group for overall (-8.59% vs -3.46%, P = 0.038) and medial (-8.51% vs -3.31%, P = 0.043) talar cartilage after the dynamic loading condition. In the combined cohort, cartilage deformation was greater after static loading compared with dynamic in overall (-8.85% vs -6.03%, P = 0.003), medial (-9.38% vs -5.91%, P = 0.043), and lateral (-7.90% vs -5.65%, P = 0.009) cartilage. US is capable of detecting differences in cartilage deformation between those with CAI and uninjured controls after standardized physiologic loads. Across both groups, our results demonstrate that static loading results in greater cartilage deformation compared with dynamic loading.

Quadriceps Strength Influences Patient Function More Than Single Leg Forward Hop During Late-Stage ACL Rehabilitation

BackgroundA comprehensive battery of tests are used to inform return to play decisions following anterior cruciate ligament (ACL) reconstruction. Performance measures contribute to patient function, but it is not clear if achieving symmetrical performance on strength and hop tests is sufficient or if a patient also needs to meet minimum unilateral thresholds.Hypothesis/PurposeTo determine the association of quadriceps strength and single-leg forward hop performance with patient-reported function, as measured by the IKDC Subjective Knee Form (IKDC), during late-stage ACL rehabilitation. A secondary purpose was to determine which clinical tests were the most difficult for participants to pass.Study DesignDescriptive Laboratory StudyMethodsForty-eight individuals with a history of ACL-R (32 female, 16 male; mean±SD age=18.0±2.7 y; height=172.4±7.6 cm; mass=69.6±11.4 kg; time since surgery=7.7±1.8 months; IKDC=86.8±10.6) completed the IKDC survey, quadriceps isometric strength, and single-leg forward hop performance. The relationship between IKDC scores and performance measures (LSI and involved limb) was determined using stepwise linear regression. Frequency counts were used to determine whether participants met clinical thresholds (IKDC 90%, quadriceps and single-leg forward hop LSI 90%, quadriceps peak torque 3.0 Nm/kg, and single-leg forward hop 80% height for females and 90% height for males).ResultsQuadriceps LSI and involved limb peak torque explained 39% of the variance in IKDC scores while measures of single-leg forward hop performance did not add to the predictive model. Nearly 90% of participants could not meet established clinical thresholds on all five tests and quadriceps strength (LSI and peak torque) was the most common unmet criteria (71% of participants).ConclusionsDuring late-stage ACL rehabilitation deficits in quadriceps strength contribute more to patient function and are greater in magnitude compared to hop test performance.Level of evidenceCross-Sectional Study, Level 3

Effects of Different Junction Parameters on Junction Conductances of Crossed Metallic Carbon Nanotubes

We have studied the effect of different junction parameters on the junction conductances made of two crossed metallic carbon nanotubes. We have found that because of the intrinsic asymmetries of the junction, forward and backward tunneling between one tube and the other are unequal. Passing a current in one tube leaded to the development of non zero voltage across the other one, a zero field Hall like conductance for the junction was found. We have found that this zero field Hall conductance relates to the contact conductance of the junction. The result also shows that the electronic properties of the junction sensitively depend on the degree of matching between the tube lattices. This matching is controlled by the crossing angel, which resulted in an intertube conductance that varied by an order of magnitude for different angles. We have derived a tunneling matrix element that coupled the low energy electronic states on the two tubes. The magnitude of the coupling was determined by the intertube separation of the crossing angle. We have found that the intrinsic symmetries of the junction created a discrepancy between the forward and backward hopping between the tubes. Using Landauer-Buttiker formalism, we have calculated the different conductances of the four terminal junctions. We have found that the contact conductance scaled inversely with the zero field Hall conductance of the junction. We have also found that the two crucial parameters in determining the conductance are the tube chiralities and the crossing angle. The obtained results were found in good agreement with previously obtained results.

Survey on Various DTN Routing Algorithms for Vehicular ADHOC Network (VANET)

Vehicle Adhoc Network (VANET) permits self-organized infrastructure. Link or Connectivity breakage or long delay (intermittent connection) is an important issue in the VANET which arises due to the dynamic topological changes. Mainly two algorithms Vehicle assisted Data Delivery (VADD) and Opportunistic routing algorithm supports for handling delay/disruption tolerant network (DTN). Intention of DTN is to create dynamic link between the sender and receiver vehicle in the case of link disruption or absence of path between two nodes and forwards the data using store carry and forward. VADD carry and forward the data as much as possible in disconnected network using intersection mode, straightway mode or destination mode. Opportunistic routing can deal the unreliable data and intermittent connectivity in VANET by considering the multiple nodes as a next hop forwarder instead of considering pre-selected single node to be the best forwarder. This paper gives the study about various opportunistic routing algorithms for handling delay/disruption tolerant network.

VLA-CR: A Variable Action-set Learning Automata-based Cognitive Routing Protocol for IoT

Internet of Things (IoT) is a heterogeneous, mixed, and uncertain ubiquitous network, which has significantly affected the concept of wireless networking. A large number of wireless devices have connected through the IoT and shared large amounts of data. So, efficient routing and forwarding data packets from the wireless devices toward gateways, which have connected to the Internet, is one of the most important issues in IoT. This paper has focused on routing and forwarding data packets in IoT. Firstly, a learning automata-based cognitive framework has been applied to integrate cognition into IoT; because current IoT lacks intelligence and cannot satisfy the increasing application performance requirements, and also adding cognition into IoT equips it with a brain and high level intelligence. Then, a new routing and forwarding protocol, which benefits from cross-layer optimization between routing and Media Access Control (MAC) layer protocols, has been proposed. In the proposed protocol a network of variable action-set learning automata establishes a route between source nodes and a corresponding gateway, by making a directed acyclic graph toward the gateway. Then, using a set of learning automata, MAC layer protocol parameters are configured to properly forward data packets hop by hop. The proposed protocol has been named VLA-CR (Variable Action-set Learning Automata-based Cognitive Routing Protocol). Based on Martingale theorem, the convergence of VLA-CR has been proved. Finally, extensive simulation experiments have been conducted to show the performance of the proposed protocol. Simulation results show the superiority of VLA-CR over several existing routing protocol in terms of end-to-end reliability, end-to-end delay, power consumption, and routing time.

ELMP: Efficient location based multicast protocol for mobile ad hoc networks

Node Location information may reduce the overalloverhead of communication for packet forwarding in Mobile Ad- Hoc Networks (MANETs). This research aims in developing Efficient Location based Multicast Protocol (ELMP) to reduce the communication and computation requirement for selection of next node (hop) for packet forwarding. To diminish the impact due to inaccurate local topology knowledge, the topology information is updated at a node in a periodic manner based on network dynamics and traffic demand. On-demand routing mechanism is used in order to reduce control overhead compared to the proactive schemes which are normally adopted in current geographic routing protocols. Proposed method procures the node position detail using GPS and tracks the effective routing algorithm to ensure communication follows with least no’s of hops and computations. This aims to prove that the proposed ELMP outperforms in all aspects such as improved energy consumption, packet delivery ratio and decreased delay, overhead.

Exercise Progression to Incrementally Load the Achilles Tendon.

The purposes of our study were to evaluate Achilles tendon loading profiles of various exercises and to develop guidelines to incrementally increase the rate and magnitude of Achilles tendon loading during rehabilitation. Eight healthy young adults completed a battery of rehabilitation exercises. During each exercise, we collected three-dimensional motion capture and ground reaction force data to estimate Achilles tendon loading biomechanics. Using these loading estimates, we developed an exercise progression that incrementally increases Achilles tendon loading based on the magnitude, duration, and rate of tendon loading. We found that Achilles tendon loading could be incrementally increased using a set of either isolated ankle movements or multijoint movements. Peak Achilles tendon loads varied more than 12-fold, from 0.5 bodyweights during a seated heel raise to 7.3 bodyweights during a forward single-leg hop. Asymmetric stepping movements like lunges, step ups, and step downs provide additional flexibility for prescribing tendon loading on a side-specific manner. By establishing progressions for Achilles tendon loading, rehabilitative care can be tailored to address the specific needs of each patient. Our comprehensive data set also provides clinicians and researchers guidelines on how to alter magnitude, duration, and rate of loading to design new exercises and exercise progressions based on the clinical need.

Muscular Coordination of Single-Leg Hop Landing in Uninjured and Anterior Cruciate Ligament-Reconstructed Individuals.

This study compared lower-limb muscle function, defined as the contributions of muscles to center-of-mass support and braking, during a single-leg hopping task in anterior cruciate ligament-reconstructed (ACLR) individuals and uninjured controls. In total, 65 ACLR individuals and 32 controls underwent a standardized anticipated single-leg forward hop. Kinematics and ground reaction force data were input into musculoskeletal models to calculate muscle forces and to quantify muscle function by decomposing the vertical (support) and fore-aft (braking) ground reaction force components into contributions by individual lower-limb muscles. Four major muscles, the vasti, soleus, gluteus medius, and gluteus maximus, were primarily involved in support and braking in both ACLR and uninjured groups. However, although the ACLR group demonstrated lower peak forces for these muscles (all Ps < .001, except gluteus maximus, P = .767), magnitude differences in these muscles' contributions to support and braking were not significant. ACLR individuals demonstrated higher erector spinae (P = .012) and hamstrings forces (P = .085) to maintain a straighter, stiffer landing posture with more forward lumbar flexion. This altered landing posture may have enabled the ACLR group to achieve similar muscle function to controls, despite muscle force deficits. Our findings may benefit rehabilitation and the development of interventions to enable faster and safer return to sport.

Single-leg forward hopping exposures adversely affect knee joint health among persons with unilateral lower limb loss: A predictive model

Single-leg hopping is an atypical, yet convenient, method of ambulation for individuals who have sustained unilateral lower limb-loss. Hopping is generally discouraged by therapists but many patients report hopping, and the potential deleterious effects of frequent hopping on knee joint health remains unclear. Mechanical fatigue due to repeated exposures to increased or abnormal loading on the intact limb is thought to be a primary contributor to the high prevalence of knee osteoarthritis among individuals with unilateral lower limb amputation. We aimed to compare knee joint mechanics between single-leg hopping and walking at self-selected paces among individuals with unilateral lower limb-loss, and estimated the associated probability of knee cartilage failure. Thirty-two males with traumatic unilateral lower limb-loss (22 transtibial, 10 transfemoral) hopped and walked at a self-selected pace along a 15-m walkway. Peak knee moments were input to a phenomenological model of cartilage fatigue to estimate the damage and long-term failure probability of the medial knee cartilage when hopping vs. walking. We estimate that each hop accumulates as much damage as at least 8 strides of walking (p < 0.001), and each meter of hopping accumulates as much damage as at least 12 m of walking (p < 0.001). The 30-year failure probability of the medial knee cartilage exceeded a “coin-flip” chance (50%) when performing more than 197 hops per day. Although a convenient mode of ambulation for persons with unilateral lower limb-loss, to mitigate risk for knee osteoarthritis it is advisable to minimize exposure to single-leg forward hopping.

Proton Transport in [BMIM+][BF4-]/Water Mixtures Near the Percolation Threshold.

The incorporation of ionic liquids into existing proton exchange membrane (PEM) materials has been shown to enhance thermal stability and improve conductivity at reduced water content. Because proton transport is dictated by an interplay between vehicular diffusion and the Grotthuss mechanism, it is expected that the nanoscale structure of the resulting ionic liquid/water networks will sensitively influence transport properties. In this work, we study proton transport in [BMIM+][BF4-]/water mixtures of systematically varying water volume fraction, focusing on concentrations near the percolation threshold in which water networks are connected over macroscopic length scales. We utilize reactive molecular dynamics within the multistate empirical valence bond (MS-EVB) framework to explicitly model Grotthuss hopping processes. Excellent agreement with experimental conductivity data is obtained within the Nernst-Einstein approximation, indicating that proton transport proceeds in a largely uncorrelated manner even at pH <0. We additionally study the changing topology of the hydrogen-bonded water network in these mixtures using percolation and graph theory analysis. We find that the proton diffusion coefficient and forward hop rate increase linearly with water content at concentrations ranging from dilute through the percolation threshold; surprisingly, we find no deviation in this trend at the percolation transition. The high concentration of BF4- anions inherently alters the fraction of Eigen and Zundel proton states, producing a net detrimental effect on proton transport rates relative to bulk water. This mechanistic insight is useful for selecting ideal ionic liquid candidates and determining the optimal ionic liquid concentration to incorporate into PEM materials.

An Enhanced Energy Optimization Routing Protocol with Fuzzy Logic in Wireless Sensor Network

Wireless Sensor Network (WSN) is a huge collection of sensor nodes deployed without any predetermined infrastructure. They are powered by batteries and energy consumption is one of the major issues in WSN. Hence to prolong the lifetime of the networks, it is important to design the energy efficient optimized routing algorithm. In this paper, two hop forwarding scheme in AODV and Fuzzy Logic is proposed to find an optimal routing protocol and intermediate node acknowledgement is deducted by the use of Fuzzy rules. The parameters such as remaining energy, data packet transmission, packet received acknowledgement and number of rounds is given as input to the fuzzy system which gives an optimized routing decision. The efficacy of the proposed algorithm is evaluated using NS2 and compared with Fuzzy-based Energy-Aware Routing Mechanism (FEARM). The simulation results shows that the Fuzzy based AODV routing algorithm reduces the energy consumption, minimizes the routing response packets and improves the network life time compared to other similar routing protocols.

Protracted alterations in muscle activation strategies and knee mechanics in patients after Anterior Cruciate Ligament Reconstruction.

Altered quadriceps muscle activity can contribute to reduced ability of the muscle to quickly generate force and appropriately attenuate landing forces, exacerbating poor landing and movement strategies commonly seen after anterior cruciate ligament reconstruction (ACLR). The purpose was to evaluate if electromyographic (EMG) activity and knee biomechanics during a single-limb forward hop task are influenced by a history of ACLR. Twenty-six individuals with a history of unilateral ACLR (age 20.2 ± 2.7years, height 1.7 ± 0.1m; weight 69.6 ± 12.4kg; time from surgery, 2.9 ± 2.7years; graft type, 21 bone-patellar-tendon bone, 5 hamstring) and 8 healthy controls (age 23.3 ± 1.8years, height 1.7 ± 0.1m; mass 66.3 ± 13.9kg) volunteered. Sagittal plane knee kinetics and EMG of the vastus lateralis were synchronized and measured using a three-dimensional motion analysis system during a single-limb forward hop task. Mixed-effect models were used to assess the effect of group on kinetic and EMG variables. Kinetic outcomes (peak and rate of knee extension moment) and temporal muscle activity and activation patterns differed between the ACLR limb and healthy-control limb. Inter-limb asymmetries in the ACLR group were observed for all variables except EMG onset time; no limb differences were observed in the healthy cohort. Years after ACLR, persistent quadriceps functional deficits are present, contributing to altered neuromuscular control strategies during functional tasks that may increase the risk of reinjury. To counteract these effects, emerging evidence indicates that clinicians could consider the use of motor learning strategies to improve neuromuscular control after ACLR. III.

Reliable Path Selection and Opportunistic Routing Protocol for Underwater Wireless Sensor Networks

The increased need to gather scientific data and the renewed drive to explore underwater natural resources has led more and more researchers to study the underwater environment. This has resulted in enormous attention being given to Underwater Wireless Sensor Networks (UWSNs) all over the world. However, UWSNs are faced with some major challenges including harsh environment, higher propagation delay, and limited battery power of the sensor nodes. To address these challenges, several routing schemes have been proposed. In this paper, we propose a routing strategy, called Reliable Path Selection and Opportunistic Routing (RPSOR) for UWSNs, which is a significantly improved version of Weighting Depth and Forwarding Area Division Depth Based Routing (WDFAD-DBR). RPSOR is based on three main factors: Advancement factor (ADV f ), which depends on the depth of current as well as next hop forwarding node; Reliability index (REL i ), which depends on the energy of the current forwarder as well as average energy in the next expected forwarding region; and Shortest Path Index (SP i ), which is calculated on the basis of number of hops to the sink and average depth of neighbors in the next expected hop. To deal with the void hole problem and improve the Packet Delivery Ratio (PDR), we follow the more reliable path towards the sink by calculating REL i for a node. At the end, we perform extensive simulations and compare our proposed scheme with WDFAD-DBR, the results of which prove that RPSOR shows better performance in terms of PDR and energy tax in comparison to WDFAD-DBR. However, the proposed work compromises end-to-end delay in sparse networks.

Methodologies for calculating decision-related event occurrence times, with applications to effective routing in diverse MANET environments

To capture the dynamics of context-aware decision making for network functions in Mobile Ad Hoc Networks (MANETs), the paper introduces the concept of Decision-Related Event Occurrence Times (DREOTs). By considering a generic scenario, the paper develops a broadly applicable analysis methodology, which produces upper and lower bounds for the tail probabilities and moments of a DREOT. The nature and effect of the decision is abstracted away to quantities called ‘decision policy impact descriptors’. These are calculated on a case-by-case basis, by considering properties of the specific decision policy and mobility pattern in hand. The power of the approach is demonstrated through a detailed application targeting the analysis of a preexisting routing protocol that bases its next hop forwarding decisions on the location and motion of the neighboring nodes. In the considered application the DREOT represents the time a node retains a message before forwarding it to the next hop and the network nodes move according to the Random Direction mobility model. The proposed methodology is seen to bring more rigorous understanding of the relationship between the retaining time and the relevant context and to yield refined expressions, whose use improves the protocol’s performance for all network conditions in a very diverse set. Furthermore, the broad applicability of the methodology is illustrated through a brief discussion of another application, not related to routing.

Fuzzy Logic Based Multi-criteria Intelligent Forward Routing in VANET

Vehicular ad-hoc network have the capability for enhancing the road safety using intelligent transportation system by communicating with each other (V–V) as well as with road side infrastructure unit (V–I) through driver information system and internet access. It becomes more challenging issue in VANET to provide a reliable multi-hop communication, due to high speed of vehicles movement, limited wireless resources, and the lose characteristic of a wireless channel. To overcome the above problem, this paper presents a fuzzy logic based multi-criteria intelligent forward routing protocol. Which is operable in dynamic network condition and compatible with both communication modes like vehicle-to-vehicle and vehicle-to-infrastructure. To select the greedy next node for data forwarding our proposed protocol calculate node stability cost and positive progress value. Here fuzzy logic based multi-criteria has been used to dynamically evaluate the node stability cost for selecting the next hop forward vehicle or road side units (RSUs), for forwarding the data reliably toward the destination. Three parameters, packet reception probability with changes of intra communication distance, speed difference and link expiration time between relay and neighbor vehicles or RSUs has been used to evaluate the weight of node using fuzzy logic. Also positive progress value has been considered to identify the distance with direction of a node from the destination at a particular time. In framework evaluation, an infrastructure-based fuzzy next hop forwarding mechanism has been presented in urban areas. The simulation results has been shown an improvement of performance of the given solution in comparison with existing protocol performance.

A novel test reliably captures hip and knee kinematics and kinetics during unanticipated/anticipated diagonal hops in individuals with anterior cruciate ligament reconstruction

Unanticipated land-and-cut maneuvers might emulate lower limb mechanics associated with anterior cruciate ligament (ACL) injury. Reliability studies on landing mechanics of such maneuvers are however lacking. This study investigated feasibility and within-session reliability of landing mechanics of a novel one-leg double-hop test, mimicking a land-and-cut maneuver, in individuals with ACL reconstruction (ACLR). Our test comprised a forward hop followed by a diagonal hop in either of two directions (medial/lateral) under anticipated and unanticipated conditions. Twenty individuals with a unilateral ACLR (aged 24.2 ± 4.2 years, 0.7–10.8 years post-surgery) performed three successful hops/direction per leg. We determined reliability (intraclass correlation coefficient [ICC]) and agreement (standard error of measurement [SEM]) of 3-dimensional hip and knee angles and moments during the deceleration phase of the land-and-cut maneuver (vulnerable for non-contact ACL injuries). Mean success rate for unanticipated hops was 71–77% and for anticipated hops 91–95%. Both limbs demonstrated moderate-excellent reliability (ICC 95% confidence intervals: 0.50–0.99) for almost all hip and knee peak angles and moments in all planes and conditions, with a few exceptions: poor-good reliability for hip and knee frontal and/or transverse plane variables, especially for lateral diagonal hops. The SEMs were ≤5° and ≤0.23 N·m/kg·m for most peak angles and moments, respectively. Our test seems feasible and showed satisfactory reliability for most hip and knee angles and moments; however, low knee abduction and internal rotation angles and moments, and moderate reliability of these moments deserve consideration. The test appears to challenge dynamic knee control and may prove valuable in evaluation during knee rehabilitation.

Opportunistic Directional Location Aided Routing Protocol for Vehicular Ad-Hoc Network

The Vehicular ad-hoc network (VANET) is an autonomous system mobile vehicle connected over a wireless link to transmit data packets in the network. It is noteworthy that vehicles are highly mobile with a limited communication range so that they change their network topology frequently. Therefore, efficient and robust data delivery in VANET is a challenging task due to dynamic network topology, unstable links, and high mobility. In this paper, an opportunistic routing protocol named Opportunistic Directional-Location Added Routing (OD-LAR) protocol proposed that uses full broadcast characteristics. The proposed protocol OD-LAR is a combination of geographical location, link quality, and angular deviation. Using all of these three metrics proposed protocol prioritizes the candidate next-hop forwarder (CNHF) nodes at the border area (BA) of the forward area (FA) towards destination node D. The proposed protocol OD-LAR assign the highest priority to CNHF node has the minimum distance from destination, good link quality, and minimum angular deviation and selects it as an optimal next hop forwarder (ONHF) node. The basic aim of the proposed OD-LAR protocol is to improve packet overhead, packet drop rates, delay, and throughput. To evaluate the performance of OD-LAR, it has simulated through network simulator-2 (NS-2) and compared with the directional-location aided routing (D-LAR) and location aided routing (LAR) protocols. Through simulated results, it has shown packet drop rate and delay is minimum in OD-LAR as compared to the D-LAR and LAR protocols.

An Intelligent Fuzzy Based Location Aided Routing in Vehicular Ad Hoc Networks

In the Vehicular Ad hoc Networks (VANET), performance is the key factor for the development of a standard routing protocol. The general characteristics of VANET are dynamic vehicle network topology and mobility. The choice of a better next forwarding hop vehicle among the available neighboring vehicles will lead better use of the route and also minimize the delays. However, there is a need for an efficient decision making in selecting the route for successful packet delivery. This paper proposes a new hybrid routing protocol called “Fuzzy assisted Location Aided Routing using Cache” (FLAR-C). FLAR-C uses a fuzzy logic technique that helps in better decision making to select the next hop for packet forwarding. Metrics like distance, direction, velocity, density and position of next hop vehicle are placed into the fuzzy logic system. And moreover, the proposed technique uses cache schemes to forward packets to the destinations under the Geocast zone. An experimental study is carried out to prove the performance of the proposed protocol and the simulation results highlights that FLAR-C is more effective in selecting the better forwarding hop for improved performance

People with patellofemoral pain have impaired functional performance, that is correlated to hip muscle capacity

ObjectiveTo (i) compare objective function in a range of tasks between people with and without patellofemoral pain (PFP); and (ii) evaluate the relationship of objective function with hip muscle capacity and self-reported function in people with PFP. DesignCross-sectional. SettingsLaboratory. ParticipantsThirty-two physically active people (16 with PFP and 16 controls). Main outcome measuresFunctional assessments included stair climbing (time), single-legged chair stand (repetitions), step down (repetitions), forward hop for distance and side hop (repetitions). Hip abductor and extensor capacity assessments included power, endurance, isometric and dynamic strength. Self-reported function included the Kujala scale and Patellofemoral sub-scale of the Knee injury and Osteoarthritis Outcome Score (KOOS-PF). ResultsThe PFP group was 15% slower climbing stairs (effect size [ES] = 0.90), performed 12% fewer chair stands (ES = 0.62) and forward hopped 20% shorter (ES = 0.79) compared to controls. Lower hip muscle strength and power correlated with lower objective function (r = 0.52–0.78). Lower Kujala scores correlated with longer stair climbing time (r = −0.53). ConclusionPeople with PFP have objective functional impairments, that are associated with reduced hip muscle capacity, indicating progressive resistance training may be beneficial. Absence of a strong correlation between self-reported, and objective, function indicates assessment of both when treating people with PFP is warranted.

Test–retest reliability and discriminative ability of forward, medial and rotational single-leg hop tests

BackgroundSingle-leg hop tests are commonly performed in the forward direction to evaluate functional performance. However, athletes move in multiple directions during pivoting sports. The first aim of this study was to examine test–retest reliability of single-leg hop tests in the forward, medial and rotational direction in non-injured athletes. Second, the discriminative ability to detect leg asymmetries with these hop tests in anterior cruciate ligament (ACL) reconstructed athletes was determined. MethodsSixteen recreational non-injured participants (eight females, eight males; 22.4 ± 1.9 years) were tested twice (one-week interval) and performed the single hop for distance (SH), triple hop for distance (TH), medial side triple hop for distance (MSTH) and 90° medial rotation hop for distance (MRH). Intraclass correlation coefficients (ICCs), standard errors of measurement (SEM) and smallest detectable differences (SDD) were calculated. Discriminative ability was determined in 32 ACL-reconstructed participants (four females, 28 males; 24.4 ± 4.6 years; six months postoperative) who performed the same hop tests once. ResultsThe ICCs ranged between 0.93 and 0.98. The SEM and SDD were respectively 2.6–4.1% and 7.2–11.3% of the mean hop distance of the group. The proportion (%) of ACL-reconstructed participants passing the ≥90% limb symmetry cut-off was 62.5 (SH), 59.4 (TH), 40.6 (MSTH) and 46.9 (MRH). ConclusionExcellent test–retest reliability of forward, medial and rotational hop tests was found. This allows clinicians to make informed interpretations of changes in hop test distances when retesting athletes. Medial and rotational hop tests are more likely to show limb asymmetries in ACL-reconstructed participants compared to forward hop tests.