Sports Sciences Commons^™

Examination Of Physiological And Perceptual Responses During Sustained, Isometric, Fatiguing, Handgrip Exercise Anchored To Ratings Of Perceived Exertion, Minyoung Kwak

Theses and Dissertations--Kinesiology and Health Promotion

The purposes of this study were to: 1) Examine the patterns of force responses relative to critical force (CF) during submaximal, fatiguing, isometric handgrip exercise anchored to different rating of perceived exertion (RPE) levels (RPE=3, 5, and 7); 2) assess the loss of force during the task and the level of performance fatigability after each RPE hold; 3) examine the time course of changes and patterns of neuromuscular [electromyography (EMG) amplitude (AMP), mean power frequency (MPF), mechanomyography (MMG) AMP and MPF, and neuromuscular efficiency (NME) (i.e. force/EMG AMP)] and muscle oxygen saturation (% SmO₂) responses during each RPE …

Effect Of Pitching Restrictions And Mound Distance On Youth Baseball Pitch Counts., Hailey Mair, Nicholas A Kenney, Timothy L Uhl, L Robert Ullery, Robert G Hosey

Physical Therapy Faculty Publications

BACKGROUND: Studies have shown that higher pitch counts are directly related to a greater incidence of elbow and shoulder pain among youth baseball pitchers.

PURPOSE/HYPOTHESIS: The purpose of this study was to examine the effect of different pitching restriction rules on the number of pitches thrown in youth baseball leagues. We hypothesized that more pitches would be thrown in leagues with inning restrictions versus leagues with pitch count restrictions as well as in leagues with a longer mound distance (from pitching mound to home plate).

STUDY DESIGN: Cohort study; Level of evidence, 2.

METHODS: Pitch count data were collected for …

Central Vs. Peripheral Vision During A Singe-Leg Drop Jump: Implications Of Dynamics And Patellofemoral Joint Stress, Junyoung Ko, Kyeongtak Song, Hoon Kim, Sae Yong Lee, Jihong Park

Athletic Training and Clinical Nutrition Faculty Publications

Landing on a single-leg without receiving direct visual information (e.g., not looking at the ground) may increase the risk of injury. We examined whether visual focus contributed to the changing lower-extremity dynamics and patellofemoral joint stress during a single-leg drop jump task. Twenty healthy volunteers visited the laboratory for three separate sessions. During each session, participants randomly performed either of two types of a single-leg drop jump task from a 30 cm high wooden box. Subsequently, participants looked at the landing spot (central vision condition) or kept their heads up (peripheral vision condition) when performing the task. Sagittal and frontal …

What Have We Learnt From Quantitative Case Reports Of Acute Lateral Ankle Sprains Injuries And Episodes Of 'Giving-Way' Of The Ankle Joint, And What Shall We Further Investigate?, Filip Gertz Lysdal, Yuehang Wang, Eamonn Delahunt, Dominic Gehring, Kyle B. Kosik, Tron Krosshaug, Yumeng Li, Kam-Ming Mok, Kati Pasanen, Alexandria Remus, Masafumi Terada, Daniel T. P. Fong

Athletic Training and Clinical Nutrition Faculty Publications

Lateral ankle sprains are a commonly incurred injury in sports. They have a high recurrence rate and can lead to the development of persistent injury associated symptoms. We performed a quantitative synthesis of published case reports documenting the kinematics of acute lateral ankle sprains and episodes of ‘giving-way’ of the ankle joint to provide a comprehensive description of the mechanisms. A systematic literature search was conducted to screen records within MEDLINE® and EMBASE®. Additional strategies included manual search of specific journals, as well as contacting researchers in relevant communities to retrieve unpublished data. Twenty-four cases were included in the quantitative …

More Elevated Fastballs Associated With Placement On The Injured List Due To Shoulder Injury, Austin V. Stone, Brooks N. Platt, Brandon S. Collofello, Aaron D. Sciascia, Timothy L. Uhl, William B. Kibler

Orthopaedic Surgery and Sports Medicine Faculty Publications

Purpose

To evaluate whether impending shoulder injury was associated with changes in pitch location or velocity immediately preceding injury.

Methods

Pitchers placed on the injured list (IL) due to a shoulder injury between 2015 and 2020 were identified in the Major League Baseball transactions database. Four-seam fastball velocity and frequency of pitch location for each pitch type was collected for each player in the season before placement on the IL and within 1 month of placement on the IL with a minimum of 55 pitches thrown of 1 type. Pitch locations were collected as identified by Baseball Savant’s Game-Day Zones. …

Blood Flow Restriction Training After Patellar Instability (Brains Trial), Benjamin D. Brightwell, Austin V. Stone, Xiaojuan Li, Peter A. Hardy, Katherine L. Thompson, Brian W. Noehren, Cale A. Jacobs

Orthopaedic Surgery and Sports Medicine Faculty Publications

Background

Patellar instability is a common and understudied condition that disproportionally affects athletes and military personnel. The rate of post-traumatic osteoarthritis that develops following a patellar dislocation can be up to 50% of individuals 5–15 years after injury. Conservative treatment is the standard of care for patellar instability however, there are no evidence-informed rehabilitation guidelines in the scientific literature. The purpose of this study is to assess the effectiveness of blood-flow restriction training (BFRT) for patellar instability. Our hypotheses are that this strategy will improve patient-reported outcomes and accelerate restoration of symmetric strength and knee biomechanics necessary to safely return …

A Muscle Cell-Macrophage Axis Involving Matrix Metalloproteinase 14 Facilitates Extracellular Matrix Remodeling With Mechanical Loading, Bailey D. Peck, Kevin A. Murach, R. Grace Walton, Alexander J. Simmons, Douglas E. Long, Kate Kosmac, Cory M. Dungan, Philip A. Kern, Marcas M. Bamman, Charlotte A. Peterson

Center for Muscle Biology Faculty Publications

The extracellular matrix (ECM) in skeletal muscle plays an integral role in tissue development, structural support, and force transmission. For successful adaptation to mechanical loading, remodeling processes must occur. In a large cohort of older adults, transcriptomics revealed that genes involved in ECM remodeling, including matrix metalloproteinase 14 (MMP14), were the most upregulated following 14 weeks of progressive resistance exercise training (PRT). Using single-cell RNA-seq, we identified macrophages as a source of Mmp14 in muscle following a hypertrophic exercise stimulus in mice. In vitro contractile activity in myotubes revealed that the gene encoding cytokine leukemia inhibitory factor ( …

Reactive Oxygen Species (Ros) And Antioxidants As Immunomodulators In Exercise: Implications For Heme Oxygenase And Bilirubin, David Travis Thomas, Nicholas R. Delcimmuto, Kyle D. Flack, David E. Stec, Terry D. Hinds Jr.

Athletic Training and Clinical Nutrition Faculty Publications

Exercise is commonly prescribed as a lifestyle treatment for chronic metabolic diseases as it functions as an insulin sensitizer, cardio-protectant, and essential lifestyle tool for effective weight maintenance. Exercise boosts the production of reactive oxygen species (ROS) and subsequent transient oxidative damage, which also upregulates counterbalancing endogenous antioxidants to protect from ROS-induced damage and inflammation. Exercise elevates heme oxygenase-1 (HO-1) and biliverdin reductase A (BVRA) expression as built-in protective mechanisms, which produce the most potent antioxidant, bilirubin. Together, these mitigate inflammation and adiposity. Moderately raising plasma bilirubin protects in two ways: (1) via its antioxidant capacity to reduce ROS and …

Combined Driving: Task-Specific Position Impacts Grip Strength Of Equestrian Athletes, Michaela M. Keener, Kimberly I. Tumlin, Nicholas R. Heebner

Athletic Training and Clinical Nutrition Faculty Publications

BACKGROUND: Loss of hand strength is a predictor of mortality in aging populations. Despite reliance on the hands to participate in equestrian driving activity, no existing studies focus on associations of hand strength to athletic performance. Therefore, this study 1) established baseline handgrip of equestrian combined drivers in standing and task-specific positions, 2) determined endurance of task-specific handgrip, 3) compared handgrip strength to normative data, and 4) evaluated associations of handgrip and equestrian-specific variables.

METHODS: There were 51 combined drivers (9 males, 42 females) ages 21-78 who completed a survey, standing handgrip, and grip strength and endurance in a task-specific …

Efficacy Of Power Training To Improve Physical Function In Individuals Diagnosed With Frailty And Chronic Disease: A Meta-Analysis, Alexander B. Sklivas, Lauren E. Robinson, Timothy L. Uhl, Esther E. Dupont-Versteegden, Kirby P. Mayer

Physical Therapy Faculty Publications

Muscle power training with emphasis on high-velocity of concentric movement improves physical functionality in healthy older adults, and, maybe superior to traditional exercise programs. Power training may also be advantageous for patients with acute and chronic illnesses, as well as frail individuals. To determine the efficacy of power training compared with traditional resistance training on physical function outcomes in individuals diagnosed with frailty, acute illness or chronic disease. PubMed (MEDLINE), CINAHL, PEDro, Web of Science, and Google Scholar. (1) at least one study group receives muscle power training of randomized controlled trial (RCT) (2) study participants diagnosed as prefrail, frail …

The Correlation Between Acl Injury & Concussion, Brandon Michael Phillips

Theses and Dissertations--Kinesiology and Health Promotion

Concussion (also known as mild traumatic brain injury) is a neurological injury that occurs after a blow to the head or neck area and can have affects to movement based on the severity of the injury. Mild traumatic brain injury has possible linkage to an increased risk of anterior cruciate ligament (ACL) injury. The purpose of this thesis was to assess the impact of prior concussion on lower extremity mechanics that are associated with risk of ACL injury. A total of 11 individuals with prior history of concussion and 11 healthy individuals without prior history of concussion (56.5 months since …

Bending The Elbow During Shoulder Flexion Facilitates Greater Scapular Upward Rotation And A More Favorable Scapular Muscle Activation Pattern, Alon Rabin, Brakha R. Tabi, Timothy L. Uhl, Zvi Kozol

Physical Therapy Faculty Publications

Context: Decreased scapular upward rotation (UR) and diminished activation of the serratus anterior (SA) and lower trapezius (LT) are often observed among patients with subacromial impingement syndrome. Maintaining the elbow fully flexed during shoulder flexion may limit glenohumeral motion due to passive insufficiency of the triceps brachii and therefore facilitate greater scapular UR and increased scapular muscle activation. Objectives: To compare scapular UR, SA, upper trapezius (UT), middle trapezius, and LT activation levels between shoulder flexion with the elbow extended (Flexion-EE) to shoulder flexion with the elbow fully flexed (Flexion-EF). This study hypothesized that Flexion-EF would result in …

Neurophysiological And Psychological Characteristics Of Individuals With History Of Lateral Ankle Sprain, Katherine Bain

Theses and Dissertations--Rehabilitation Sciences

Lateral ankle sprain (LAS) is among the most common lower limb musculoskeletal injuries impacting both the general and sport populations. Even more problematic is that approximately 70% of individuals who sustain an LAS develop residual deficits. Of that subgroup, roughly 40% develop chronic ankle instability (CAI). Chronic ankle instability is a clinical diagnosis defined by the presence of ongoing impairments following the initial LAS which may include perceived instability, pain, mechanical instability, and episodes of giving way during physical activity. Not all who sustain multiple ankle sprains or experience residual deficits fit the clinical diagnosis criteria for CAI; yet may …

The Utilization Of Physical Literacy To Understand Physical Activity In Individuals With A History Of Anterior Cruciate Ligament Reconstruction, Rachel Renee Kleis

Theses and Dissertations--Rehabilitation Sciences

Injury to the anterior cruciate ligament (ACL) is common in physically active populations. Anterior cruciate ligament reconstruction (ACLR) is commonly performed after injury in order to restore joint stability and knee function and return patients to desired levels of physical activity. However, not everyone will return to their pre-injury levels of sport after surgery and recent evidence reveals that individuals with a history of ACLR are less likely to meet the recommended physical activity guidelines. Specifically, previous literature has reported that individuals with a history of ACLR take fewer daily steps and participate in less moderate-to-vigorous physical activity compared to …

Hindlimb Suspension In Wistar Rats: Sex-Based Differences In Muscle Response, Marie Mortreux, Megan E. Rosa-Caldwell, Ian D. Stiehl, Dong-Min Sung, Nicholas T. Thomas, Christopher S. Fry, Seward B. Rutkove

Athletic Training and Clinical Nutrition Faculty Publications

Ground-based animal models have been used extensively to understand the effects of microgravity on various physiological systems. Among them, hindlimb suspension (HLS), developed in 1979 in rats, remains the gold-standard and allows researchers to study the consequences of total unloading of the hind limbs while inducing a cephalic fluid shift. While this model has already brought valuable insights to space biology, few studies have directly compared functional decrements in the muscles of males and females during HLS. We exposed 28 adult Wistar rats (14 males and 14 females) to 14 days of HLS or normal loading (NL) to better assess …

Association Between Pitch Break On The 4-Seam Fastball And Slider And Shoulder Injury In Major League Baseball Pitchers: A Case-Control Study, Brooks N. Platt, Anthony J. Zacharias, Caitlin Conley, Lindsay Hockensmith, Nicholas Stockwell, Aaron Sciascia, Austin V. Stone

Orthopaedic Surgery and Sports Medicine Faculty Publications

Background: Few specific risk factors are known for shoulder injury in professional pitchers. New pitch-tracking data allow for risk stratification based on advanced metrics.

Purpose/Hypothesis: The purpose of this study was to determine the association between shoulder injury, pitch frequency, and pitch metrics (velocity, total break, break angle, and spin rate) for the 4-seam fastball, curveball, and slider. We hypothesized that more frequent use of the 4-seam fastball would be associated with shoulder injury.

Study Design: Case-control study; Level of evidence, 3.

Methods: The Major League Baseball (MLB) database was queried for pitchers who had been placed on the injury …

A Nation-Wide Survey Of High School Baseball Coaches’ Perceptions Indicates Their Arm Care Programs Play A Role In Injury Prevention, Kyle A. Matsel, E. E. Weiss, R. J. Butler, Matthew C. Hoch, Philip M. Westgate, Terry R. Malone, Timothy L. Uhl

Physical Therapy Faculty Publications

Background
Arm care programs consisting of upper extremity strengthening and stretching have been recommended for injury prevention for pitchers of all ages. There has been no investigation into high school baseball coaches’ usage and perceptions of arm care programs to mitigate physical impairments associated with injuries in baseball players.

Hypothesis/Purpose
The purpose of this study was to investigate the current usage of arm care programs by high school baseball coaches. The primary objective was to determine if coaches use group-based or individualized arm care programs. The secondary objective sought to determine if the use of arm care programs is influenced …

Identifying Risk Factors Of Upper Extremity Injuries In Collegiate Baseball Players: A Pilot Study, Robert Slowik, Christopher Morris, Matthew C. Hoch, Timothy L. Uhl

Physical Therapy Faculty Publications

Background
Repetitive pitching places tremendous forces on the shoulder and elbow which can lead to upper extremity (UE) or lower extremity (LE) overuse injuries.

Purpose
The purpose of this study was to evaluate pre-season physical measurements in collegiate baseball players and track in-season baseball throwing volume to determine which factors may predict throwing overuse injuries.

Study Design
Retrospective Cohort study.

Methods
Baseline preseason mobility, strength, endurance, and perception of function were measured in 17 collegiate baseball pitchers. Participants were then followed during the course of the season to collect rate of individual exposure, estimated pitch volume, and rating of perceived …

Post-Operative Rehabilitation For Scapular Muscle Reattachment: A Case Report, Wendy Burke, W. Ben Kibler, Timothy L. Uhl

Physical Therapy Faculty Publications

Background and Purpose: Scapular muscle detachment is a rare orthopedic problem that has been described in the literature in patients following traumatic events involving traction, direct trauma, or a motor vehicle accident. The purpose of this case report is to describe the post-operative rehabilitation following scapular muscle reattachment surgery. Unique to this case report is the patient's perspective, an orthopedic physical therapist with 25 years of experience.

Case Description: A 47-year-old female physical therapist experienced a traction injury to bilateral upper extremities during a medical procedure resulting in bilateral rhomboid, and bilateral lower trapezius muscles were detached from the medial …

Sex And Age Comparisons In Neuromuscular And Biomechanical Characteristics Of The Knee In Young Athletes, Erin R. Pletcher, Travis J. Dekker, Scott M. Lephart, Tim C. Sell

Sports Medicine Research Institute Faculty Publications

Background: The identification of risk factors for injury is a key step for musculoskeletal injury prevention in youth sports. Not identifying and correcting for injury risk factors may result in lost opportunity for athletic development. Physical maturation and sex affect these characteristics, which may indicate the need for both age and sex-based injury prevention programs.

Hypothesis/Purpose: This study examined age and sex differences in knee strength, static balance, jump height, and lower extremity landing biomechanics in school- and high school-age athletes.

Study Design: Cross-sectional.

Methods: Forty healthy school aged (10.8±0.8 yrs) and forty high school (16.8±0.8 yrs) athletes completed isokinetic …

Line Hops And Side Hold Rotation Tests Load Both Anterior And Posterior Shoulder: A Biomechanical Study, Margie K. Olds, Nicole Lemaster, Kelsey Picha, Cody Walker, Nicholas R. Heebner, Timothy L. Uhl

Sports Medicine Research Institute Faculty Publications

Background: Clinical tests should replicate the stressful positions encountered during sport participation. Evaluating the kinetic and electromyographical demands of clinical tests enables clinicians to choose appropriate tests for specific sports.

Purpose: To describe the shoulder forces and muscle activation levels during closed chain functional tests of Line Hops (LH) and Side Hold Rotation (SHR).

Study Design: Descriptive biomechanical study.

Methods: Ten asymptomatic participants were examined in a university laboratory. Two functional tests were evaluated using three-dimensional video analysis and electromyography to measure shoulder forces, moments, and muscular activity levels.

Results: SHR produced a peak average posterior translation force of 4.84 …

Injury Rates In Major League Baseball During The 2020 Covid-19 Season, Brooks N. Platt, Timothy L. Uhl, Aaron D. Sciascia, Anthony J. Zacharias, Nicole G. Lemaster, Austin V. Stone

Physical Therapy Faculty Publications

Background: The 2020 Major League Baseball (MLB) season was drastically altered because of the COVID-19 pandemic. The changes included an extended layoff between March and July as well as a shortened preseason.

Purpose/Hypothesis: To determine the incidence and epidemiology of MLB injuries in the abbreviated 2020 season compared with prior seasons. We hypothesized that there was an increase in the overall injury rate in the 2020 season compared with the 2018-2019 seasons and that it equally affected all body regions.

Study Design: Descriptive epidemiology study.

Methods: The MLB transactions database was queried to find players who had been placed on …

Applications Of The Critical Power Model To Dynamic Constant External Resistance Exercise: A Brief Review Of The Critical Load Test, Haley C. Bergstrom, Taylor K. Dinyer, Pasquale J. Succi, Caleb C. Voskuil, Terry J. Housh

Kinesiology and Health Promotion Faculty Publications

The study and application of the critical power (CP) concept has spanned many decades. The CP test provides estimates of two distinct parameters, CP and W′, that describe aerobic and anaerobic metabolic capacities, respectively. Various mathematical models have been used to estimate the CP and W′ parameters across exercise modalities. Recently, the CP model has been applied to dynamic constant external resistance (DCER) exercises. The same hyperbolic relationship that has been established across various continuous, whole-body, dynamic movements has also been demonstrated for upper-, lower-, and whole-body DCER exercises. The asymptote of the load versus repetition relationship is defined as …

Effects Of Racing Surface And Turn Radius On Fatal Limb Fractures In Thoroughbred Racehorses, Michael L. Peterson, Wayne T. Sanderson, Nurlan Kussainov, Sarah Jane Hobbs, Patti Miles, Mary C. Scollay, Hilary M. Clayton

Biosystems and Agricultural Engineering Faculty Publications

North American Thoroughbred racing is conducted on three types of surfaces—dirt, turf, and synthetic. The tracks are oval, and races are run counterclockwise. The loading on right and left limbs is expected to differ as a function of turn radius, banking, surface, and gait asymmetry. Hind limbs and forelimbs also have different functions related to propulsion and turning, respectively. This study uses the Equine Injury Database for race starts from 1 January 2009 through 31 December 2014, to compare injury rates across participating North American racetracks. The data are limited to catastrophic injuries in which horses died or were euthanized …

Mechanical Deviations And Verbal-Cue Altered Gait In The Femoroacetabular Impingement Syndrome Population, Walter Menke

Theses and Dissertations--Kinesiology and Health Promotion

Femoroacetabular impingement syndrome (FAIS) is an abnormal physical hip morphology that causes functional changes and pain during gait. Mechanical gait differences in this population require further biomechanical investigation to elucidate characteristics unique to this group. Fixed speed gait trials were performed on force plates and analyzed in addition to isokinetic strength testing to find a multitude of biomechanical variables including joint moment, joint power, joint work, and peak joint angle. This work has discovered evidence of muscular deficits at the hip, specifically hip extension, as well as knee joint power contributions to gait when compared to controls. These findings suggest …

Comparison Of The Times To Exhaustion, Physiological, Perceptual, And Neuromusuclar Responses During Constant Heart Rate, Constant Vo2, And Constant Power Exercise, Pasquale Jiovanni Succi

Theses and Dissertations--Kinesiology and Health Promotion

The purposes of this study were to: 1) Determine if there are differences in the sustainability of exercise when anchored at critical heart rate (CHR), the VO₂ associated with CHR (VO₂CHR), or the power output associated with CHR (PCHR); 2) examine the patterns of responses in power output, metabolic (heart rate [HR], VO₂, respiration rate [RR]), neuromuscular (electromyographic [EMG] amplitude [AMP], mean power frequency [MPF], mechanomyographic [MMG] AMP and MPF, perceptual (rating of perceived exertion [RPE]), and muscle oxygenation responses (%SmO₂) during exercise anchored by HR, VO₂, and power output; and …

Examination Of Sex- And Intensity-Specific Fatigue During Bilateral Leg Extension Exercise, Taylor Kayln Dinyer

Theses and Dissertations--Kinesiology and Health Promotion

The purposes of this study were to: 1) examine sex-related differences in the performance of repetitions to failure below (CL_-10%, CL_-20%) and above (50%, 60%, 70%, and 80% 1RM) the critical load (CL) to make inferences regarding the mechanisms responsible for variability in the performance of repetitions to failure at varying loads; 2) examine the time course of neuromuscular and muscle oxygen saturation responses during the performance of repetitions to failure below and above the CL; 3) to make inferences regarding motor unit activation strategies used to maintain force during the completion of repetitions below and …

Examination Of Sex- And Limb-Specific Fatigue During Unilateral, Isometric Forearm Exercise, Caleb Christian Voskuil

Theses and Dissertations--Kinesiology and Health Promotion

The purpose of this study was to examine the effects of unilateral, isometric handgrip holds to failure for the dominant (Dm) and non-dominant (NDm) limb on ipsilateral ([IPS] exercised side) and contralateral ([CON] non-exercised side) performance fatigability. Twenty individuals participated in this study (Men [n =10]; Women [n = 10; Composite Demographics: Age: 22.2 years; Height: 174.4 cm; Body Mass: 75.0 kg) and completed three visits. Two, 6 s maximal voluntary isometric contractions (MVICs) for the Dm and NDm limb were performed during visit 1, followed by a familiarization of the fatigue test. Visits 2 and 3 included an isometric, …

Effect Of Blood Flow Restriction Training On Functional And Self-Reported Outcomes In Female Runners With Patellofemoral Pain, Lauren Nicole Erickson

Theses and Dissertations--Rehabilitation Sciences

Background: Patellofemoral pain (PFP) is the leading cause of lower extremity injury in female runners, significantly limiting running ability and becoming chronic in nearly 50% of the cases. This condition, which presents as pain around (peripatellar) or behind (retropatellar) the patella, is associated with significant weakness of the quadriceps and gluteal musculature, as well as altered movements mechanics. The challenge for clinicians is designing an effective treatment program to reduce pain and improve function without causing symptoms to flare. Blood flow restriction training (BFRT) is a relatively new training method within rehabilitation that involves placing a pressurized cuff to the …

Development Of A Field Expedient Screening Tool For The Coach To Identify Musculoskeletal Risk Factors In Baseball Players, Kyle Andrew Matsel

Theses and Dissertations--Rehabilitation Sciences

Identification of musculoskeletal (MSK) injury risk factors in baseball players can be challenging particularly for youth and high school coaches. Many baseball coaches lack a sports medicine and/or strength and conditioning staff to assist with injury prevention initiatives. Given the extensive responsibilities in managing the team and preparing the players for athletic competition, little time remains to focus on injury prevention and arm care programs. Furthermore, assessment, diagnosis, and management of MSK impairments is outside the scope of practice and expertise of baseball coaches. However, educating and empowering the coach to efficiently screen their players for potentially injury producing MSK …