Lawrence W Weiss

The University of Memphis | U of M · College of Health Sciences

Daugherty, HJ, Weiss, LW, Paquette, MR, Powell, DW, and Allison, LE. Potential predictors of vertical jump performance: Lower extremity dimensions and alignment, relative body fat, and kinetic variables. J Strength Cond Res 35(3): 616-625, 2021-The association of structural and kinetic variables with restricted vertical jump (RVJ) displacement with...

Running promotes better cardiovascular health and has positive effects on the musculoskeletal system in older adults. However, older adults have lower ankle plantarflexor torques and positive powers during running, and exhibit changes in plantarflexor morphology than young adults. Since older runners who run as much as younger runners exhibit youth...

Smith, RE, Paquette, MR, Harry, JR, Powell, DW, and Weiss, LW. Footwear and sex differences in performance and joint kinetics during maximal vertical jumping. J Strength Cond Res XX(X): 000-000, 2018-This investigation examined the effects of footwear and sex on vertical jump displacement and joint power contributions. Twenty-three young adults wit...

Swearingen, JT, Weiss, LW, Smith, WA, Stephenson, MD, and Schilling, BK. Potential utility of a loaded treadmill protocol for tactical athletes. J Strength Cond Res 32(3): 610-616, 2018-Aerobic capacity is an important variable for tactical athletes, with V _ O 2 max being the most direct way of estimating it in a laboratory setting. A mode-specifi...

Aerobic capacity is an important variable for tactical athletes, with VO2max being the most direct way of estimating it in a laboratory setting. A mode-specific protocol involving fixed-weight, torso-borne loads was assessed in the current study. On four separate days, 15 men (Age 22.1 ± 2.7 years, mass 85.1 ± 10.6kg, height 179.0 ± 7.7cm) performe...

The effects of a recovery drink on overreaching induced by high frequency, high power resistance exercise was assessed. Resistance trained men were assigned to a supplemented (SUP, n = 8), placebo (PL, n = 3) or control (CON, n = 6) groups. All groups completed two weeks of familiarization training using the barbell squat. In week three, SUP and PL...

PurposeMany physiological maladaptations persist after overreaching and overtraining resistance exercise (RE). However, no studies have investigated changes in mitogen-activated protein kinases (MAPK) after overtraining in humans, despite their critical role regulating exercise-induced muscular adaptations. The purpose of this study was to describe...

Little research has been done examining the most physically demanding tasks a SWAT officer may perform in the line of duty. Our objective was to analyze the rankings of tasks by SWAT officers based on frequency, difficulty, and importance and assess if training is addressing traits needed for successful task completion. A survey was designed using...

Vertical jump (VJ) capability is integral to the level of success attained by individuals participating in numerous sport and physical activities. Knowledge of factors related to jump performance may help with talent identification and/or optimizing training prescription. Although myriad variables are likely related to VJ, this study focused on det...

Body dimensions may influence various types of physical performance. This study was designed to establish the reliability and precision of bilateral lower-body dimensions using surface anatomic landmarks and either sliding calipers or goniometry. Fifty university students (25 men and 25 women) were measured on two separate occasions separated by 48...

Indoor positioning is a research area that is gaining lots of attention recently. Its applications cover a wide area where the technology can be incorporated into consumer electronic products. For example, in the case of in-house navigation, indoor positioning technology can be utilized by handheld products to provide location identification, and t...

The purpose of this investigation was to examine the effects of footwear on kinetics and lower extremity electromyographic (EMG) activity during the vertical jump (VJ) and standing long jump. Fifteen men performed the 2 jump types in 3 footwear conditions: barefoot, minimal shoes, and cross-training shoes. Jump displacement and kinetic data were co...

The purpose was to examine the acute effect of pre-exercise static stretching on barbell power and velocity during the bench press exercise. Forty male high school athletes performed 1 repetition maximum (1 RM) testing and were divided into either a static stretching (SS), or a no stretching (NS) protocol. Subjects performed 1 set of 3 repetitions...

Non-functional overreaching (NFOR) is detrimental to resistance exercise (RE) performance. Research concerning sensitive and sport specific methods that identify NFOR is sparse, and inconsistencies of results may be due to differences in testing modalities. PURPOSE: The purpose of this study was to compare muscle performance using different testing...

The dorsal muscles of the lower torso and extremities have often been denoted the 'posterior chain.' These muscles are used to support the thoracic and lumbar spine as well as peripheral joints including the hip, knee, and ankle on the dorsal aspect of the body. This study investigated relative muscle activity of the hamstring group and selected su...

The purposes of this study were to establish stability reliability of a measure of lower body anaerobic power, the Kansas Squat Test; (KST), and to compare the KST with the commonly used Wingate anaerobic test (WAnT) for lower body power. Fourteen resistance trained men (mean ± SD; age = 24.2 ± 3.6 yrs.) performed both the KST and the WAnT twice on...

Objective: To establish the stability reliability, precision, and minimum value for detecting real differences for quadriceps angle (Q-angle) measurements based on standardized protocols and surface goniometry. Design: An intratester reliability study. Setting: University research laboratory. Participants: Fifty-two healthy, young, relativel...

A study was carried out to investigate the potential use of B-mode ultrasound for measuring subcutaneous fat thickness at two arm sites. Data from two similar groups of college students (n = 64) were collected for the following purposes: (1) to determine at each of two separate arm sites if a single measurement of subcutaneous fat taken in the midd...

The current U.S. Navy Physical Readiness Test (PRT) measures aerobic fitness and muscular endurance via a 1 1/2 mile run and curl-up/push-up tests, respectively. Nine new modalities were recommended to either replace or supplement the current PRT. Personnel and civilians (N = 179) were recruited from a local Navy base and participated in all modali...

The upright row is commonly used to develop the deltoid and upper back musculature. However, little information exists concerning muscle recruitment during variations of this exercise. Sixteen weight-trained men completed two repetitions each in the upright row with three grip conditions; 50, 100, and 200% of the biacromial breadth (BAB). The load...

Drop vertical jumps (DVJs) stimulate enhanced countermovement loading as would occur with a run-up before jumping. A variety of performance variables have been associated with DVJ performance including ground contact time (GCT), reactive strength index (RSI), eccentric utilization ratio (EUR), and elasticity index (EI). This study examined the stab...

This investigation was designed to determine if relatively small manipulations of squat load and the inclusion of selected morphologic variables might augment the explained variance in vertical jump (VJ) displacement. Fifty-two university students (27 women and 25 men) with weight training experience served as subjects. All were assessed for body f...

Vertical jump performance is often assessed using jump-and-reach tests. The exact procedure used for determining standing reach height and jump height has a large effect on the resultant displacement. The purpose of this investigation was to determine the influence of 4 methods of standing reach height measurement and Vertec jump height measurement...

Numerous reports exist concerning relationships between muscle fiber types or myosin heavy chain expression and in vivo human muscle performance. Whereas in vitro high power performances in single muscle cells are most associated with type IIB/X fibers expressing primarily MHC IIb/x, these relationships are not always observed for in vivo volitiona...

The direct acquisition of ground reaction force data during isoinertial resistance tasks typically requires a force platform. As this is not always practical, alternative devices have been used to estimate dynamic force by directly measuring other variables and then using inverse dynamics to calculate it. For example, linear position and linear vel...

Athletes often perform intense workouts with short intervals between sessions. The purpose of this investigation was to examine the ability to repeat a high volume chest press workout following a 48 hour rest interval between sessions, as part of a larger intervention. 15 resistance trained men (age 26 ± 4) were recruited from the university popula...

The purpose of this investigation was to examine the effects of a 5-week, low-cost unstable surface balance training program in sexagenarians. Nineteen men and women (60-68 years; 83.7 +/- SD kg) were randomly assigned to a control or training group. The training group performed various balance activities on air-filled rubber disks for 5 weeks. Eac...

Previous investigations have demonstrated leg strength deficits in persons with Parkinson's disease (PD) as compared to neurologically-normal adults. However, the exact mode of contraction by which strength is assessed may determine how closely such deficits are related to functional performance. The purpose of this study was to better understand t...

The purpose of this investigation was to compare the kinetic characteristics of the power clean exercise using either free weight or machine resistance. After familiarization, 14 resistance trained men (mean +/- SD; age = 24.9 +/- 6.2 years) participated in two testing sessions. During the initial testing session, one-repetition maximum performance...

The p38 mitogen activated protein kinase (MAPK) pathway responds to extracellular stress, and contributes to apoptosis. It has also been previously shown that chronic high intensity overtraining can lead to a variety of negative adaptations. PURPOSE: To examine the previously unstudied effect of high intensity resistance exercise overtraining on re...

Court sports often require more frequent changes of direction (COD) than field sports. Most court sports require 180 degrees turns over a small distance, so COD in such sports might be best evaluated with an agility test involving short sprints and sharp turns. The purposes of this study were to (a) quantify vertical and horizontal force during a C...

Court sports often require more frequent changes of direction (COD) than field sports. Most court sports require 180= turns over a small distance, so COD in such sports might be best evaluated with an agility test involving short sprints and sharp turns. The purposes of this study were to (a) quantify vertical and horizontal force during a COD task...

The extracellular regulated protein kinase (ERK) pathway has been shown to influence growth hormone. However, it is not clear effect of overtraining on ERK. PURPOSE: To examine the effect of high intensity overtraining on resting ERK pathways in skeletal muscle. METHODS: Sixteen previously weight trained men (age [yrs]=20.2±.05, hgt [m]=1.80±0.02,...

Schilling, BK, Falvo, MJ, Karlage, RE, Weiss, LW, Lohnes, CA, and Chiu, LZF. Effects of unstable surface training on measures of balance in older adults. J Strength Cond Res 23(4): 1211– 1216, 2009—The purpose of this investigation was to examine the effects of a 5-week, low-cost unstable surface balance training program in sexagenarians. Nineteen...

The purpose of this study was to determine the acute effects of a spectrum of eccentric loads on force, velocity, and power during the concentric portion of maximal-effort jump squats utilizing a repeated measures design. Thirteen resistance-trained men (age = 22.8 +/- 2.9 years, weight = 87.1 +/- 11.8 kg, 163.5 +/- 28.6 kg squat 1 repetition maxim...

Previous research on overtraining due to excessive use of maximal resistance exercise loads [100% 1 repetition maximum (1 RM)] indicates that peripheral muscle maladaptation contributes to overtraining-induced performance decrements. This study examined the cellular and molecular responses of skeletal muscle to performance decrements due to high-re...

The effects of contextual interference on learning pistol-shooting skills in a natural training environment were examined. The shooting skills consisted of three "stages" with different requirements for the skill variations commonly used in the field. 12 participants were randomly assigned into one of two practice conditions, blocked vs serial. Fol...

Power is an integral aspect of many sports. Although power output of the lower body is often measured during jumping and cycling movements, much less is known about power as pertains to the upper body musculature. Recently, isoinertial methods--with constant gravitational load--of power testing have become common, but little is known of the reliabi...

The purpose of this study was to determine if supplementation with a liquid multi-vitamin/mineral would improve anaerobic exercise performance. Fourteen resistance-trained men performed a 30-second cycle sprint and one set of squat exercise on 2 separate days before and following 8 weeks of supplementation with either a liquid multi-vitamin/ minera...

Thirty-six healthy men with varying degrees of physical training background performed maximal-effort isometric and isoinertial knee extensor actions, with relative loads equal to 40% and 70% of one-repetition maximum. Force, velocity, and power were derived from force and linear position transducers at 500 Hz. Biopsies were taken from the vastus la...

This investigation was designed to determine the effects of astaxanthin on markers of skeletal muscle injury. Twenty resistance trained men (mean +/- standard error of the mean : age , 25.1 +/- 1.6 y; height, 1.79 +/- 0.02 m; weight, 86.8 +/- 4.4 kg) were assigned to either a placebo (1732 mg safflower oil, n =10) or astaxanthin (BioAstin; 1732 mg...

This investigation estimated the amount of variance in voluntary in vivo muscle performance that can be explained by relative myosin heavy chain (MHC) isoform expression. The role of the relative expression of these proteins in relation to in vitro force and velocity performance is well understood, but the in vivo model is less clear. Twenty-two me...

Strength augmentation has been demonstrated in resistance-trained men subsequent to 4 days of training abstinence. However, this phenomenon was exhibited in an unusual circumstance in which the exercise test (seated heel raise) primarily involved an isolated skeletal muscle (soleus) that is normally comprised almost exclusively of 1 fiber type. It...

Resistance exercise can result in both potentiating and fatiguing responses. These responses can acutely affect performance, which may affect subsequent exercise sessions in the same day. The purpose of this investigation was to study the acute neuromuscular responses to two high intensity training sessions in the same day. Twelve recreationally tr...

Twelve men either performed 10 weeks of timed circuit weight training 3 days week(-1) (CWT; n=8; X+/-SE; age=23.6+/-1.8 years), or were part of a sedentary control group (n=4; age=20.5+/-1.0 years). Significance was P<0.05 for all analyses. The CWT program significantly increased 1 repetition maximum (1 RM) strength for nine of 10 exercises (15-42%...