scholarly journals Landing Styles Influences Reactive Strength Index without Increasing Risk for Injury

2018 ◽  
Vol 02 (02) ◽  
pp. E35-E40
Author(s):  
Dana Guy-Cherry ◽  
Ahmad Alanazi ◽  
Lauren Miller ◽  
Darrin Staloch ◽  
Alexis Ortiz-Rodriguez
Keyword(s):  
Muscle Activity ◽  
Knee Flexion ◽  
Gluteus Maximus ◽  
Ground Reaction Forces ◽  
Drop Jump ◽  
Strength Index ◽  
Jumping Performance ◽  
Landing Mechanics ◽  
Reaction Forces ◽  
Increasing Risk

AbstractThe aim was to determine which three landing styles – stiff (ST), self-selected (SS), or soft (SF) – exhibit safer landing mechanics and greater jumping performance. Thirty participants (age: 26.5±5.1 years; height: 171.0±8.8 cm; weight: 69.7±10.1 kg) performed five trials of three randomized drop jump (40 cm) landing styles including SF (~60° knee flexion), ST (knees as straight as possible), and SS. Knee flexion and valgus angles and kinetics were measured. An electromyography system measured muscle activity of the gluteus maximus, quadriceps, hamstrings, tibialis anterior, and gastrocnemius. Reactive strength index (RSI) was used to measure jumping performance. ANOVAs were used to compare the three landings. All landings differed in knee flexion (p<0.001; effect size (η2): 0.9) but not valgus (p=.13; η2:.15). RSI (mm·ms-1) showed differences for all jumps (p<0.001; η2: 0.7) with SS (0.96) showing the highest value, then ST (0.93), and SF (0.64). Ground reaction forces were different between jumps (p<0.001; η2: 0.4) with SF (1.34/bodyweight (bw)) showing lower forces, then SS (1.50/bw), and ST (1.81/bw). No between-jump differences were observed for EMG (p>0.66; η2: 0.3). No landing demonstrated valgus landing mechanics. The SS landing exhibited the highest RSI. However, the 1.8/bw exhibited by the ST landing might contribute to overload of musculotendinous structures at the knee.

scholarly journals Machine Learning-Based Estimation of Ground Reaction Forces and Knee Joint Kinetics from Inertial Sensors While Performing a Vertical Drop Jump

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7709
Author(s):  
Serena Cerfoglio ◽  
Manuela Galli ◽  
Marco Tarabini ◽  
Filippo Bertozzi ◽  
Chiarella Sforza ◽  
...  
Keyword(s):  
Neural Network ◽  
Machine Learning ◽  
Knee Joint ◽  
Field Analysis ◽  
Ground Reaction Forces ◽  
Drop Jump ◽  
Joint Moments ◽  
Data Set ◽  
Joint Kinetics ◽  
Reaction Forces

Nowadays, the use of wearable inertial-based systems together with machine learning methods opens new pathways to assess athletes’ performance. In this paper, we developed a neural network-based approach for the estimation of the Ground Reaction Forces (GRFs) and the three-dimensional knee joint moments during the first landing phase of the Vertical Drop Jump. Data were simultaneously recorded from three commercial inertial units and an optoelectronic system during the execution of 112 jumps performed by 11 healthy participants. Data were processed and sorted to obtain a time-matched dataset, and a non-linear autoregressive with external input neural network was implemented in Matlab. The network was trained through a train-test split technique, and performance was evaluated in terms of Root Mean Square Error (RMSE). The network was able to estimate the time course of GRFs and joint moments with a mean RMSE of 0.02 N/kg and 0.04 N·m/kg, respectively. Despite the comparatively restricted data set and slight boundary errors, the results supported the use of the developed method to estimate joint kinetics, opening a new perspective for the development of an in-field analysis method.

Concurrent Tactile Feedback Provided by a Simple Device Increased Knee Flexion and Decreased Impact Ground Reaction Forces During Landing

2016 ◽  
Vol 32 (3) ◽  
pp. 248-253 ◽  
Author(s):  
Boyi Dai ◽  
Mitchell L. Stephenson ◽  
Samantha M. Ellis ◽  
Michael R. Donohue ◽  
Xiaopeng Ning ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Low Cost ◽  
Cruciate Ligament ◽  
Tactile Feedback ◽  
Simple Device ◽  
Ground Reaction Forces ◽  
Knee Valgus ◽  
Peak Knee ◽  
Reaction Forces ◽  
Anterior Cruciate

Increased knee flexion and decreased knee valgus angles and decreased impact ground reaction forces (GRF) are associated with decreased anterior cruciate ligament (ACL) loading during landing. The purpose of this study was to determine the effect of tactile feedback provided by a simple device on knee flexion and valgus angles and impact GRF during landing. Kinematic and kinetic data were collected when 28 participants performed baseline, training, and evaluation jump-landing trials. During the training trials, the device was placed on participants’ shanks so that participants received tactile feedback when they reached a peak knee flexion angle of a minimum of 100°. During the evaluation trials, participants were instructed to maintain the movement patterns as they learned from the training trials. Participants demonstrated significantly (P < .008) increased peak knee flexion angles, knee flexion range of motion during early landing (first 100 ms of landing) and stance time, decreased impact posterior and vertical GRF during early landing and jump height, and similar knee valgus angles during the evaluation trials compared with the baseline trials. Immediately following training with tactile feedback, participants demonstrated landing patterns associated with decreased ACL loading. This device may have advantages in application because it provides low-cost, independent, and real-time feedback.

Changes in Muscle Activity and Ground Reaction Forces with Differing Shoes

2011 ◽  
Vol 43 (Suppl 1) ◽  
pp. 314
Author(s):  
Bryson H. Nakamura ◽  
Heidi A. Orloff ◽  
Sean D. Field-Eaton ◽  
Erienne V. Olesh
Keyword(s):  
Muscle Activity ◽  
Ground Reaction Forces ◽  
Reaction Forces

Landing Constraints Influence Ground Reaction Forces and Lower Extremity EMG in Female Volleyball Players

2004 ◽  
Vol 20 (1) ◽  
pp. 38-50 ◽  
Author(s):  
Mark D. Tillman ◽  
Rachel M. Criss ◽  
Denis Brunt ◽  
Chris J. Hass
Keyword(s):  
Muscle Activity ◽  
Repeated Measures ◽  
Muscle Activation ◽  
Vertical Jump ◽  
Lateral Loading ◽  
Initial Contact ◽  
Ground Reaction Forces ◽  
Vertical Loading ◽  
Volleyball Players ◽  
Reaction Forces

The purposes of this study were to analyze double-limb, dominant-limb, and nondominant-limb landings, each with a two-footed takeoff, in order to detect potential differences in muscle activity and ground reaction forces and to examine the possible influence of leg dominance on these parameters. Each of the three jump landing combinations was analyzed in 11 healthy female volleyball players (age 21 ± 3 yrs; height 171 ± 5 cm, mass 61.6 ± 5.5 kg, max. vertical jump height 28 ± 4 cm). Ground reaction forces under each limb and bilateral muscle activity of the vastus medialis, hamstrings, and lateral gastrocnemius muscles were synchronized and collected at 1,000 Hz. Normalized EMG amplitude and force platform data were averaged over five trials for each participant and analyzed using repeated-measures ANOVA. During the takeoff phase in jumps with one-footed landings, the non-landing limb loaded more than the landing limb (p= 0.003). During the 100 ms prior to initial contact, single-footed landings generated higher EMG values than two-footed landings (p= 0.004). One-footed landings resulted in higher peak vertical loading, lateral loading, and rate of lateral loading than two-footed landings (p< 0.05). Trends were observed indicating that muscle activation during one-footed landings is greater than for two-footed landings (p= 0.053 vs.p= 0.077). The greater forces and rate of loading produced during single-limb landings implies a higher predisposition to injury. It appears that strategic planning and training of jumps in volleyball and other jumping sports is critical.

A Finite Element Analysis of a Subject Specific Single-Leg Drop Landing at Varied Heights

2011 ◽  
Author(s):  
Chi-Yin Tse ◽  
Hamid Nayeb-Hashemi ◽  
Ashkan Vaziri ◽  
Paul K. Canavan
Keyword(s):  
Knee Flexion ◽  
Reaction Force ◽  
Acl Injury ◽  
Ground Reaction Forces ◽  
Vertical Ground Reaction Force ◽  
Element Analysis ◽  
Drop Landing ◽  
Subject Specific ◽  
Reaction Forces ◽  
Vertical Ground

The pathomechanics of knee anterior cruciate ligament (ACL) injury related to the female athlete is of high interest due to the high incidence of injury compared to males participating in the same sport. The mechanisms of ACL injury are still not completely understood, but it is known that single-leg landings, stopping and cutting at high velocity are some of the non-contact mechanisms that are causing these injuries. This study analyzed a subject specific analysis of a single-leg drop landing that was performed by a female subject at 60%, 80% and 100% of her maximum vertical jump. The femur, tibia, articular cartilage, and menisci were modeled as 3-D structures and the data collected from the motion analysis was used to obtain the knee joint contact stresses in finite element analysis (FEA). The four major ligaments of the knee were modeled as non-linear springs. Material properties of previously published studies were used to define the soft tissue structures. The articular cartilage was defined as isotropic elastic and the menisci were defined as transverse isotropic elastic. Two different styles of single-leg landings were compared to one another, resembling landing from a basketball rebound. The first landing style, single-leg arms up (SLAU), produced larger knee flexion angles at peak ground reaction forces, while single-leg arms across (SLAX) landings produced higher peak vertical ground reaction forces along with lower knee flexion angles. The mean peak vertical ground reaction force was 2.9–3.5 bodyweight for SLAU landings, while they were 3.0–3.8 for SLAX landings. The time to peak vertical ground reaction force with SLAU landings were 69 ms (60%), 60 ms (80%), and 55 ms (100%); SLAX landings were 61 ms (60%), 61 ms (80%), and 51 ms (100%).

Functional knee brace use effect on peak vertical ground reaction forces during drop jump landing

2012 ◽  
Vol 20 (12) ◽  
pp. 2405-2412 ◽  
Author(s):  
Neetu Rishiraj ◽  
Jack E. Taunton ◽  
Robert Lloyd-Smith ◽  
William Regan ◽  
Brian Niven ◽  
...  
Keyword(s):  
Ground Reaction Forces ◽  
Drop Jump ◽  
Knee Brace ◽  
Jump Landing ◽  
Reaction Forces ◽  
Vertical Ground ◽  
Vertical Ground Reaction Forces
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