Guillermo J. Noffal's research while affiliated with California State University, Fullerton and other places
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Publications (81)
Collegiate cross country runners are at risk for running related injuries (RRI) due to high training volume and the potential for aberrant lower extremity biomechanics. However, there is a need for prospective research to determine biomechanical risk factors for RRI. The purpose of this study was to prospectively compare ankle, knee, and hip kinema...
WITH THE GROWTH IN POPULARITY OF CORE TRAINING, IT IS IMPORTANT THAT THERE IS A CLEAR UNDERSTANDING OF HOW TO BEST TAILOR THESE EXERCISES TO SAFELY MEET THE NEEDS OF DIFFERENT INDIVIDUALS. EXTENSIVE RESEARCH HAS SHOWN THAT TRAINING THE CORE MUSCLES ISOMETRICALLY, THAT IS WITHOUT BENDING THE SPINE, IS SAFE AND MAY HELP REDUCE THE INCIDENCE OF BACK I...
As runners age, the likelihood of developing osteoarthritis (OA) significantly increases as 10% of people 55+ have symptomatic knee OA while 70% of people 65+ have radiographic signs of knee OA. The lateral-medial shear force (LMF) and knee adduction moment (KAM) during gait have been associated with cartilage loading which can lead to OA. Foot rot...
Background: Foam rolling is a popular activity utilized by strength and conditioning coaches as it is believed to increase muscle length and break up fibrous adhesions located in connective tissue. However, there is little research investigating the effects of foam rolling on athletic performance. Objective: The purpose of this study was to investi...
The purpose of this study was to determine the effect of foot strike patterns and converted foot strike patterns on lower limb kinematics and kinetics at the hip, knee, and ankle during a shod condition. Subjects were videotaped with a high speed camera while running a 5km at self-selected pace on a treadmill to determine natural foot strike patter...
Although running stairs is often used in sport conditioning programs, at present, little research has examined the effect of stair climb training on sprint power. The purpose of this study was to investigate the effects of running stairs either one-stair (1S) or two-stairs (2S) at a time on power. Fourteen male college track & field athletes were r...
It is known that proper proximal to distal sequencing of body rotations is important in the production of high club head velocities in the golf swing. Since these rotations originate at the pelvis, it is not clear how differences in pelvic kinematics are related to essential determinants of ball flight. One essential ball flight measure that has no...
SUCCESS IN MANY ATHLETIC AND SPORTING ACTIVITIES MAY BE ENHANCED BY THE ABILITY TO OPTIMIZE MUSCULAR POWER OUTPUT. THIS ARTICLE WILL PRESENT THE BIOMECHANICAL DEFINITIONS, CHARACTERISTICS, AND APPLICATIONS OF POWER IN SPORT.
Traditionally, golf research and instruction have focused on the kinematics of the golf swing; while relatively little attention has been paid to the three-dimensional representing the change in these forces throughout the golf swing. If they are just represented by a few discreet variables, much of the variability is lost. Therefore, this study us...
If the efficiency of human movement patterns could be improved using exercise, this could lead to more effective musculoskeletal disease-injury prevention and rehabilitation programs. It has been suggested that an efficient squat movement pattern emphasizes the use of the large hip extensors instead of the smaller knee extensors. The purpose of thi...
Currently, little research has been conducted using body weight reduction (BWR) as a means to enhance vertical jump. The purpose of this study was to determine the effects of different elastic cord assistance levels on vertical jump height (JH), takeoff velocity (TOV), relative ground reaction force (rGRF), relative impact force (RIF), and descent...
Surfing is a dynamic sport that is multidirectional in nature and requires peak performance in variable ocean conditions. Its growing popularity among the female population has stirred curiosity as to whether women can and will 1 day face their male counterparts in head-to-head competition at the top levels. The purpose of this study was to examine...
Remote voluntary contractions (RVC) are described as muscle activation remote from but concurrent with the activation of a prime mover in an exercise. Previous studies have shown that this phenomenon may elicit augmented results when using it concurrently with another action. PURPOSE: The purpose of this study was to evaluate the effect of hand gri...
Remote voluntary contractions (RVCs) are described as a muscle action of the prime mover while performing a simultaneous muscle action with another part of the body. Previous studies have shown that RVCs may elicit augmented performance of the prime mover. The purpose of this study was to evaluate the effect of RVCs on knee extensor rate of velocit...
Considering the importance of the vertical jump in several sports, an optimal warm-up protocol may help athletes perform at their maximum level. The purpose of this study was to investigate the potentiating effects of different levels of external resistance (weighted vest) during box jumps on vertical jump performance. Twenty resistance trained men...
Golf has the potential to keep people active well into their later years. Injuries to the target side knee have been reported in golfers, yet no mechanisms for these injuries have been proposed. The loads on the knee during the golf swing may be insufficient to cause acute injury, yet they may be a factor in the progression of overuse/degenerative...
The vertical jump is a common movement performed in several sports. Considering the importance of this movement, an optimal warm-up protocol may help athletes perform at their maximum level. The purpose of this study was to investigate the potentiating effects of different levels of external resistance (weight vest) during box jumps on vertical jum...
Previous research has investigated the force-time curve characteristics of isometric muscle actions, however, few have addressed their relationship to the kinematics of dynamic movements. The purpose of this study was to investigate relationships between dynamic kinematics [high pull peak velocity, high pull rate of velocity development, vertical j...
Vertical jump performance may be influenced by force production there by improving performance. The purpose of this study was to evaluate the relationship between force production and vertical jump performance. Forty-eight healthy students (age men 24.68+/−5.05y women 25.63 +/−7.92y, height men 177.07 +/−8.42cm women 167.24 +/−8.37, body mass men 7...
Previous research has investigated the force-time curve characteristics of isometric and dynamic muscle actions; however, few studies have addressed their relationship to dynamic exercise velocity-time variables. The purpose of this study was to investigate relationships between velocity-time characteristics (high pull and vertical jump peak veloci...
High-force activities have demonstrated postactivation potentiation (PAP) and may enhance performance in athletes; however, the efficacy of high-force activities to generate PAP in recreationally trained men remains unclear. The purpose of this study was to investigate the effect of high-force back squat volume on vertical jump (VJ) height, ground...
Falls may occur because of a deficiency in the ability to rapidly step in the desired direction. Previous models developed to predict rapid step ability have been based on balance, video analysis, or uniplanar isokinetic performance. The purpose of this investigation was to determine the effects of multiplanar velocity-spectrum training of the hip....
Little is known about the velocity-specific adaptations to training utilizing movement velocities in excess of 300 degrees x s(-1). The purpose of this investigation was to determine the effects of 4 weeks of slow (60 degrees x s(-1)) vs. fast (400 degrees x s(-1)) velocity training on rate of velocity development (RVD), peak torque (PT), and perfo...
Stretching in the warm-up has been shown to decrease several muscular performance variables, but the dose-response of this effect is unknown. This study documented the change in isometric grip strength over ten trials in a convenience sample of young adults randomly assigned to control (n=22) or repeated bouts of 10-s static stretches of the wrist...
Stretching prior to vigorous physical activity has been shown to decrease high-force muscular performance, but little is known about the effect of stretching on speed and accuracy movements. Serving percentage and radar measurements of ball speed were studied to examine the acute effect of stretching on tennis serve performance. Eighty-three tennis...
One of the possible mechanisms leading to shoulder injury may be a strength imbalance between those muscles that accelerate the upper limb and those responsible for deceleration. Many studies have examined shoulder balance through a concentric strength ratio of external and internal shoulder rotator muscles.
A functional external eccentric-to-inter...
To help instructors in evaluating innovations in biomechanics instruction, a standardised test of the key concepts taught in the introductory biomechanics course was developed. The Biomechanics Concept Inventory (BCI) consists of 24 questions that test four prerequisite competencies and eight biomechanics competencies. Three hundred and sixty seven...
Citations
... Gerçekleştirilen bu ilk çekiş bir deneme olarak kabul edildi ve daha sonra bu test, tam dinlenme aralığı verilerek iki kez tekrarlandı ve her sporcu için en iyi sonuçlar kilogram(kg) cinsinden skor olarak kaydedildi (9,10,11,12). Sırt kuvvetinin ölçümleri Takei marka sırt ve bacak(Back and Lift) dinamometresi kullanılarak belirlendi (13,14,15). Ölçümler öncesinde sporculara beş dakika süren bir ısınma protokolü uygulandı. ...
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... Studies investigating changes in vertical jump height incorporate many different methods to render athletes fatigued. These methods include long-duration running [7], knee extensor fatigue [9], plantarflexor fatigue [6], continuous jumping protocols [8,10,11], and different jumping styles such as drop jumps [12] and squat jumps [13]. Each protocol is undoubtedly effective at achieving fatigue; however, none can be assured to fatigue the participant in the same manner as a sport with frequent jumping. ...
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... This is the first study to date to examine this issue in professional soccer players although the results of the present study align with prior work conducted on professional rugby players using only plyometric exercises to induce PAP (36). Previous research using jumping exercises as CA have also reported an acute improvement in CMJ performance (2,3,37). De Villareal et al. (37) compared various types of warm-ups in volleyball players. ...
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... The increase in balance regulation with the utilization of the cutaneous system may also be true when performing squats in bare feet (BF). Changes in kinematics occur as different musculature is recruited throughout the squat; different footwear causes these musculature changes (11). In weightlifting shoes (WLS) ( Figure 1A) a rigid midsole and heel lift increases the amount of ankle plantar flexion (12). ...
Reference: The Effects of Footwear on Squat Movements
... The few studies that have prospectively examined risk factors for RRI in male and female collegiate XC runners have linked RRI to female athlete triad risk factors, hip abduction strength, pre-season injury, large mileage increases, poor sleep quality, and several biomechanical running factors. [6][7][8] Impaired hip abductor performance contributes to contralateral pelvic drop during gait and has been directly related to instability of the lower kinetic chain. 8 In the collegiate population, authors have found associations between hip abductor strength and medial tibial stress syndrome 8 and iliotibial band syndrome (ITBS). ...
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... As individuals age, participation in previously accessible leisure activities can be compromised through diminished capabilities and negative societal expectations [4]. Golf is, however, a popular sport for older adults and an important source of physical activity [5,6]. The population of golfers in Europe consists of 84% of golfers older than 40 years [7]. ...
... It has also been suggested that the use of core training to enhance spinal stability can help prevent injuries of the lumbar spine and lower extremities (12,14,15,20). This may be of benefit to both athletes and general populations alike because it has been stated that approximately up to 70-85% of all people in society experience lower back pain (LBP), with it being the leading cause of limited exercise participation among people younger than 45 years of age (1,22,27,36). McGill (20) outlined that a lack of lumbar stability may lead to micromovements, which can lead to tissue degeneration and pain. ...
Reference: The Pallof Press
... In 2004, Schleihalf conducted a study in which the Measurement of Active Drag System (MAD-System) was used to measure the propulsive force of swimmers during swimming. This study found that the swimming velocity could not increase indefinitely with the increase in their stroke rates (Schleihauf, 2004). A study published in 2008 that was conducted by Sanders et al. confirmed this finding (Sanders et al., 2008). ...
... While many studies have investigated gait modifications to reduce the knee adduction moment in walking, less is known about the effects of gait modifications on running mechanics. A recent study assessed the effects of purposeful external and internal rotation (to maximum comfort levels) during running in otherwise healthy adults [35]. The previous study successfully reduced knee adduction moments using external and internal foot rotations compared to runners' preferred (normal) pattern [35]. ...
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... (6,4,14,22) stated that, as in our study, dynamic warming has positive effects on vertical jump performance. However, (19,11) stated in their study that dynamic warming did not reveal any positive effect on vertical jump performance. In addition to these studies (23,18), their studies show that applying dynamic mobility exercises in addition to dynamic warm-up results in more positive results than the dynamic warm-up protocol applied alone. ...