Effects of Using Wedged-Weightlifting Shoes While Performing a Front Squat

Wedged-weightlifting shoes may contribute to a better squatting postural technique by allowing for an increase in ankle dorsiflexion, an increase in hip flexion, and a decrease in the amount of trunk lean. Purpose: To examine how wedged-weightlifting shoes affect peak power output, trunk lean, hip flexion, and ankle dorsiflexion during the performance of a front-squat. Methods: Six participants (167.875±20.13 lbs., 20.67±1.51 yrs.) completed five-repetition squatting trials while standing on a Bertec force plate. Force data were collected at 100 Hz using the Biopac Acknowledge system during these trials. Simultaneously, the trials were video recorded at 50 Hz in the sagittal plane. Five body landmarks (mid-trunk, hip, knee, ankle, base of the 5th metatarsal, and heel) were digitized using the Vicon Motus Motion Analysis System to generate a lower body model to measure lower extremity kinematics. Squatting trials were completed under two different shoe conditions (barefoot and wedged-weightlifting shoes) and two different loads (no-load and loaded at 50% 1RM). An initial laboratory visit two days prior to data collection was used to measure a 1RM. The middle three repetitions of the five-repetition sequence were analyzed. Ground reaction force data were used to determine peak positive and negative power during each squat repetition. Digitized position data were used to compute trunk, hip, knee and ankle joint angular kinematics. Results: A two-way repeated measure ANOVA was used to compare the shoe and load conditions. Shoe type (F(1,5)=7.81, p=.04, hp2=.61) and load (F(1,5)=24.72, p=.004) significantly affected peak negative power production. Load accounted for about 83% of the change seen in negative power production (hp2 =.832); as the load increased, the squatter’s negative power increased. Negative peak power occurs during the eccentric, or downward, movement of the squat. The means(SD) peak negative power output for wedge-weightlifting shoes, -1874.8(426.4) W, and load, -1242.0(417.1) W. Load (F(1,5)=18.94, p =.007) significantly affected the ankle angle and accounted for about 79% of change (hp2=.79), causing a decrease in ankle dorsiflexion. The mean(SD) ankle dorsiflexion under the load condition for wedged-weight lifting shoes, 50.9±(6.4)degrees, and barefoot, 49.71±(7.6)degrees. Conclusion: Although previous studies have suggested that wedged-weightlifting shoes affect performance of squatting, this study found that the wedged-weightlifting shoes did not affect the overall performance of the front squat

Investigating the Effect of Hand Position on Hand Force and Rotation Time When Performing a Freestyle Flip-Turn

Havriluk (2004) found that an increase in hand force will increase a swimmer’s velocity. While the effect of hand force on a swimmer’s velocity has been studied, the forces produced by the hands as well as the effect of forearm position on hand force production during a freestyle flip-turn has not been investigated. PURPOSE: To investigate the effect of forearm orientation on freestyle flip-turn performance. METHODS: A convenience sample of ten experienced swimmers (6 Female, 4 Male, 20 ± 1.15 years) was recruited to participate. Prior to data collection, participants completed an accommodation session to familiarize them with the techniques and protocol. Freestyle flip-turns were performed with both a swimming approach and a kicking only approach under two forearm position conditions: (1) pronated so that the palms faced upward and (2) supinated so that the palms faced downward. Rotation time in the turn, defined from initial downward movement of the feet prior to the turn to the instant the feet contact the wall, was measured using underwater video collected at 50 Hz during the trials using a swimming approach. Peak hand force was measured using a differential pressure transducer system (Aquanex, Inc.) during the trials using a kicking approach. A paired samples t-Test was used to compare rotation time between hand conditions. Hand force data were analyzed using a 2x2 (forearm position x hand) repeated measures ANOVA. RESULTS: The mean (sd) rotation times were 0.849 (0.075) s and 0.885 (0.094) s for the pronated condition and supinated condition, respectively. Rotation time was significantly faster under the pronated condition (p = 0.046). The mean (sd) peak force measurements were 6.76 (3.02) lbs, 5.67 (2.82) lbs, 4.82 (2.41) lbs, and 4.60 (2.51) for the left and right hand under the pronated and supinated condition, respectively. No significant main effect on hand force was found for forearm position (p = 0.146), and hand (p = 0.071). No significant interaction was found between forearm position and hand (p = 0.300). CONCLUSION: This study provides novel evidence that performing a freestyle flip-turn with the hands in the pronated position will lead to a faster rotation time and that there is no significant effect of hand position on hand force production during a freestyle flip-turn. As a majority of the participants felt more comfortable performing freestyle flip-turns with their hands in the pronated position, it is possible that additional accommodation to the novel technique is required to comfortably perform freestyle flip-turns with supinated forearms

Effect of Four Week Medicine Ball Training on a Peak Ground Reaction Force & Peak Moments in Collegiate Lacrosse Players

TACSM Abstract Effect of four week medicine ball training on a peak ground reaction force & peak moments in collegiate lacrosse players. DAKOTA B SKINNER, SCOTT MCLEAN, & JIMMY SMITH Department of Kinesiology; Southwestern University; Georgetown, TX Category: Undergraduate Advisor / Mentor: McLean, Scott ([email protected]) ABSTRACT Background: Medicine ball training has been shown to improve performance in baseball batting (Szymanski et al., 2007), and handball-throwing (Raeder, Fernandez, & Ferrauti, 2015). Given the similarity of the kinetic link dynamics of these activities with those of a lacrosse shot, a medicine ball training program may offer a similar performance benefit for a lacrosse shot. Purpose: The purpose of the present study was to investigate the effect of medicine ball training on peak ground reaction force (GRF) and peak GRF moments generated by collegiate level lacrosse players performing a overhand lacrosse shot. Methods: Sixteen collegiate lacrosse players volunteered to participate in this study. The control group (n = 8) and treatment group (n = 8) both participated in the same four-week lacrosse offseason program. This consisted of lacrosse practice 4 days a week as well as lifting 3 days a week. In addition, the treatment group participated in medicine ball training 3 days a week for 4 weeks. Medicine ball training consisted of 4-6 medicine ball exercises lasting 10-12minutes per session. Overhand lacrosse shot consisted of an approach such that their lead foot landed on a force plate. Force plate was sampled at 200 Hz, vertical GRF, and GRF moments about the X, Y, and Z axes were recorded at peak value for each kinetic measure. Medicine ball throw consisted of lead foot perpendicular to the length of the football field with trail foot shoulder width apart. Participants squatted with arms extended, and released the ball with maximal effort. Analyses of covariance were used to analyze peak GRF in the Z direction, peak moments in the X, Y, and Z directions, as well as distance achieved by a maximal effort medicine ball throw. Results: Average peak vertical GRF was similar before and after training for both the control group (1188 + 173 N and 1172 + 199 N, respectively) and treatment group (1206 + 130 N and 1172 + 199 N, respectively) (F1= .043, p = .84). Average peak moment in the X direction was similar before and after training for both the control group (67 + 57Nm and 92 + 28Nm, respectively) and treatment group (75 + 37Nm and 67 + 25Nm, respectively) (F1 = 3.07, p = .10). Average peak moment in the Y direction was similar before and after training for both the control group (63 + 23Nm and 87 + 39Nm, respectively) and treatment group (66 + 37Nm and 76 + 40Nm, respectively) (F1 = .273, p = .61). Average peak moment in the Z direction was similar before and after training for both the control group (25 + 10Nm and 30 + 6Nm, respectively) and treatment group (24 + 9Nm and 25 + 12Nm) (F1 = 1.41, p =.26). Average medicine ball throw distance was similar before and after training for the control group (12.75 + 0.76m and 12.60 + 1.06m, respectively) but the treatment increased their throw by nearly 1.0 m after training (12.96 + 1.31m and 13.69 + 1.22m, respectively) (F1 = 4.392, p = .056, η2 = .253). Conclusion: Despite a mild improvement in medicine ball throw, a four-week medicine ball training program had little effect on an overhand lacrosse shot

Wrist Immobilization: Does Elbow and Shoulder Overcompensation Occur When Performing Drinking and Hammering Tasks?

Wrist orthoses, which immobilize or reduce motion at the wrist, may cause difficulties in performing daily tasks as they may affect other nearby joints and muscles of the upper extremity. Previous studies have generally focused on compensatory shoulder movements, not elbow movements, when wearing wrist orthoses. The purpose this study was to determine whether wrist immobilization results in compensatory movements of both the elbow and shoulder. Specifically, this study examined joint movement of the elbow and shoulder joints when performing a drinking and hammering task while wearing a wrist orthosis. Informed consent was received from all participants prior to participation in this study. This study was approved by the Southwestern University Institutional Review Board for Human Research. A convenience sample of twenty healthy adults (21.1±1.0 yrs, 1.72±0.08 m, 68.5±10.6 kg) was recruited to participate in this study. Each participant performed both a drinking and hammering task with and without a wrist orthosis three times. Thus, each participant performed six drinking motions and six hammering motions. A Liberty D-ring static wrist splint and two twin-axis electro-goniometers were used. Compensatory movement was defined in terms of joint excursion, or the change in joint motion throughout the performance of the task. Two 2 x 2 (condition x joint) repeated measures analyses of variance were used to analyze differences in joint excursion of the elbow and shoulder joints during the two tasks for the orthosis condition (orthosis, no orthosis). There was not a significant interaction between joint movement and orthosis on joint excursion (F(1,19) = 2.13, p = 0.16, η² = 0.10) for the drinking task. There was also not a significant interaction between joint movement and orthosis on joint excursion for the hammering task (F(1,19) = 2.35, p = 0.14, η² = 0.11). These results indicate that movement of one joint together with the wearing of the orthosis did not have an effect on joint excursion of the other joint. The results of the study support the use of wrist orthosis as it found that wrist orthosis usage does not cause compensatory movements of the elbow and shoulder. The proper choice of an immobilization or supportive device must be determined by the therapist to better improve functionality

Comparison of Sagittal Plane Knee Walking Kinematics When Wearing Over-The-Counter Support Devices

PURPOSE: To compare the effect of wearing a knee compression sleeve and a hinged knee brace on kinematics of the knee to not using a support device while walking in healthy college students. METHODS: A convenience sample of 20 participants with no lower extremity surgical or injury history in the past 6 months was recruited for this study. All participants provided informed consent prior to beginning participation. A 12-camera motion analysis system was used to track the three-dimensional motion of sixteen passive reflective markers attached to the lower extremities of each subject according to the VICON Lower Extremity Plug-in Gait model. Each participant then completed one trial of overground walking at a self-selected speed for each of three knee support conditions (three trials total); no external knee support (NO), wearing a knee compression sleeve(CO), wearing an over-the-counter supportive knee brace with hinges (BR). Maximum and minimum knee angles in the sagittal plane were measured during the stance and swing phases. Range of motion (ROM) for each phase was computed as the difference between the maximum and minimum angles. Data were analyzed using one-way repeated measures ANOVA. RESULTS: Minimum sagittal plane knee angle during the stance phase, -0.2(3.8), 3.8(3.6), and -5.7(3.9) degrees for the NO, CO, and BR conditions respectively, significantly differed between support conditions (F (2,30) = 54.21, p \u3c 0.001). Maximum sagittal plane knee angle in the stance phase, 9.2(8.7), 12.6(7.5), and 2.5(8.4) degrees for the NO, CO, and BR conditions respectively, significantly differed between support conditions (F (2,30) = 42.596, p \u3c 0.001). Sagittal plane knee ROM during the stance phase, 9.4(6.2), 8.8(5.9), and 8.2(5.6) degrees for the NO, CO, BR conditions respectively, did not differ between conditions. Minimum sagittal plane knee angles during the swing phase, 29.9(5.6), 32.6(7.5), and 22.4(8.4) degrees for the NO, CO, and BR conditions respectively, significantly differed between support conditions (F (2,30) = 15.946, p \u3c 0.001). Maximum sagittal plane knee angles during the swing phase, 56.4(6.5), 59.2(7.2), and 47.3(9.9) degrees for the NO, CO, and BR conditions respectively, significantly differed between support conditions (F (2,30) = 62.9, p \u3c 0.001). Sagittal plane knee ROM during the swing phase, 26.5(7.3), 26.5(9.1), and 24.9(6.5) degrees for the NO, CO, BR conditions respectively, did not significantly differ in between conditions. CONCLUSION: For both the stance and swing phases, use of the compression sleeve maintained a more flexed knee than the no support condition. Conversely use of the hinged brace resulted in a more extended position than the no support condition during both the stance and swing phases. Performing gait with a more extended knee position may alter the ability of the knee to absorb shock. Therefore, medical professionals should be consulted before using an over-the-counter hinged knee brace

The Metabolic Cost of Pushing versus Carrying a Golfbag

The two most common non-motorized methods for transporting golf clubs in recreational and amateur golf are carrying a double strap bag or pushing a wheeled cart. The transportation method of golf clubs can have a direct impact on the necessary metabolic, musculoskeletal and cardiorespiratory requirements of golf performance. PURPOSE: To compare the metabolic cost of pushing versus carrying a golf bag. METHODS: Twenty two participants (18 Male, 3 Female, 24.2±8.9 yrs, 176.6±14.5 cm, and 76.2±14.5 kg) were recruited for one session in which they walked one mile while carrying and one mile while pushing a 25lb golf bag (determined as the average weight of a tournament bag for 5 male and 5 female collegiate golfers). Half of the participants completed the carrying condition first while the remaining participants completed the pushing condition first. All testing was performed on an indoor track. An approximate pace of 3.5mph during each walk was maintained by checking the time every 1/16 mile at which point feedback was provided to the participant to speed up, slow down, or maintain pace. It was required that each trial be completed with a time corresponding to ±5% of the 3.5 mph target pace. The walking trials were separated by a 10-minute recovery period. VO2 and HR were recorded for each transportation method using the PNOE (Athens, Greece) portable metabolic measurement system and Polar (Bethpage, NY) heart rate monitor. The use of the PNOE device required participants to breathe through a mask, which sealed the nose and mouth, for the duration of both walks. The device was removed during the recovery period. Steady state VO2 and average HR were computed for the five-minute period between minute 7 and minute 12 of each trial. Steady state VO2 and average HR were compared between walking conditions using a paired t-test. RESULTS: The mean±SD VO2 and HR were 1.48±0.19 L/min and 118.2±17.3 bpm, respectively for the carry condition and 1.34±0.17 L/min and 110.4±17.9 bpm, respectively for the push condition. Pushing the cart resulted in a significant 10.4% reduction in VO2 (t19=1.73, p19=1.73, pCONCLUSION:This study provides novel evidence that transporting a competition golf bag using a pushcart significantly reduces metabolic cost as compared to carrying. Thus, these data support utilizing a pushcart and shows that removing the load of equipment from the body has the potential to reduce fatigue experienced by the golfer. Currently within the golf community and especially within the demographic of college aged and younger golfers, there is a stigma around utilizing a pushcart. There has been no published study thus far that focuses on providing empirical evidence on the metabolic cost of pushing versus carrying a golf bag and therefore no evidence to support the choice of either method from an energy cost standpoint. Given the significant reduction in metabolic cost observed during the pushing method in this study, further study is warranted to see how the mode of transporting equipment would affect metabolic cost during an actual golf round

The Effects of Cup Stacking and Video Game Play on the Performance of a Manual Dexterity Task

ABSTRACT Dexterity and hand-eye coordination are important in daily life, and various methods of improving these skills have been developed. Most of the methods have been technological, brain training games that aren’t physically strenuous and make the participant feel as though they are just playing a game. Cup stacking and video gaming have been used throughout the United States in schools for improving motor skills and hand-eye coordination because they offer various simulations of scenarios requiring motor, visual and cognitive coordination. Purpose: To determine the effects of different types of gaming on dexterity in college aged participants. Methods: The participants were 40 students enrolled at Southwestern University. A SPEED STACKS® set of 12 cups and timing mat were set up on a table, along with a nut and bolt, and the novel, The Hunger Games. Another station was set up with Mario Kart 8 on the Nintendo® Wii. One trial at each station was completed by each participant, leading to 40 control trials, 40 cup stacking trials, and 40 video game trials. Upon completing randomized challenge on three separate days, participants assembled a nut a bolt and were timed using SPEED STACKS® timing mat. Data were recorded and analyzed in a repeated measures ANOVA. Results: A repeated measures ANOVA revealed a significant effect of cup stacking (5.69 sec ± .215) and video game play (5.79 sec ± .196) on dexterity F(2,78) = 46.205, p \u3c .002. Bonferroni post hoc tests revealed that cup stacking elicited a reduction in dexterity times when compared to the control group (5.69 ± .215 s vs 5.86 ± .199 s, respectively, p \u3c 0.05). It was also revealed that video game play elicited a reduction in dexterity times when compared to the control group, (5.79 ± .196 s vs 5.86 ± .199 s, respectively, p \u3c 0.05). It was found that cup stacking elicited quicker dexterity times than video game play (5.69 ± .215 s vs 5.79 ± .196 s, respectively, p \u3c 0.05). Conclusion: Results suggest that cup stacking provides a greater effect on dexterity than video game play. This study suggests that completing a physical hands on activity is more beneficial to maintaining dexterity than playing a video game, although both types of activities provide a significant effect on dexterity compared to the control group

The Effectiveness of the Critical Power Model on Prescribing Elements of Intermittent Exercise

Intermittent exercise is a valuable method of training, consisting of numerous interrelated factors. The critical power model has been used to administer interval training programs; however, it has not been used to accurately prescribe elements of intermittent exercise. PURPOSE: This study aimed to use individual critical power models to prescribe elements of intermittent exercise. METHODS: Ten male athletes, mean (sd) age and mass 19.6 (1.4) years and 77.8 (8.1) kg performed three phases of testing on a cycle ergometer: 1) familiarization, one learning trial to establish a starting point for subsequent tests; 2) establishment of individual W/t relationship from [Eq 1], i.e. t = W’ / (W – WCP), 4 bouts of exercise designed to elicit fatigue in 2-15 minutes; 3) intermittent exercise, 3 bouts of work with predicted number of work/recovery cycles (n = 5) of 60/60 s, 120/60 s, and 60/120 s. The elements of these bouts were prescribed using [Eq 2], i.e. n = W’ / ((Ww – WCP)tw – (WCP – Wr)tr) and estimates of W’ and CP from phase 2 of testing. One sample t-tests were used to compare the number of cycles actually completed to the predicted value of 5 cycles for each intermittent exercise bout. A repeated-measures ANOVA was used to compare the effect of intermittent exercise on the number of work/recovery cycles completed across conditions. RESULTS: The mean (sd) completed work/recovery cycles were 4.64 (0.47), 4.65 (1.10), and 3.70 (0.80), for the 60/60 s, 120/60 s, and 60/120 s trials, respectively. Results of the t-tests suggested that actual values were not significantly different from predicted for 60/60 s and 120/60 s (t(9) = -2.39, p = 0.04; t(9) = -1.01, p = 0.34), but were for 60/120 s (t(9) = -5.14, p \u3c 0.01). Results of the rANOVA suggested that the mean completed work/recovery cycles was significantly different across conditions (F(2,18) = 3.99, p = 0.04). DISCUSSION: These data suggest that using [Eq 2], with estimates of W’ and CP from [Eq 1], to prescribe elements of intermittent exercise can be successful for trials with short recovery periods

The Effect of Cardiovascular Drift on the Efficacy of Exercise Prescription

TACSM Abstract – The Effect of Cardiovascular Drift on the Efficacy of Exercise Prescription KATHERINE FORESTER, JIMMY SMITH, Ph.D., and SCOTT MCLEAN, Ph.D. Kinesiology; Southwestern University; Georgetown, TX Category: Undergraduate ABSTRACT Due to the difficulty in measuring metabolic cost in the field, heart rate (HR) is often used to prescribe exercise intensity. Purpose: To examine the effect of cardiovascular drift (CVdrift) on the efficacy of exercise prescription (ExRx). Methods: Eight women with a mean (sd) age 21.6(2.0) years, body mass 70.9(11.0) kg, height 163.7(6.0) cm, and VO2max of 33.7(4.2) mL/kg/min, each performed two cycling trials for 30 to 45min at work rates that elicited 50% and 70% of VO2max. HR (bpm) and VO2 (mL/kg/min) were recorded throughout each trial and values at the beginning, middle, and end of exercise across both intensities were compared using 3 x 2 two-way repeated measures ANOVAs. Repeated measures ANOVAs were used to compare responses across time within each exercise intensity. Results: Estimated work rates accurately elicited 50% and 70% of HRmax and VO2max at 5 min of exercise. For HR, there was a significant effect of both time (F (1,2) = 124.8, p \u3c .001) and intensity (F (1,1) = 312.0, p \u3c .001), and a significant interaction between time and intensity (F (1,2) = 6.14, p = 0.012). There was a significant effect of time on HR at both the 50% intensity (F (1,2) = 40.74, p \u3c .001) and 70% intensity (F(1,2) = 101.9, p \u3c .001). VO2 increased significantly due to both time (F (1,2) = 6.63, p = .009) and intensity (F (1,1) = 312.0, p \u3c .001) but there was no interaction, and the significant effect of time was only at the 70% intensity (F (1,2) = 3.90, p = .05). Discussion: The main finding of this study was that HR and metabolic demand became increasingly dissociated across time at both intensities. This dissociation was more pronounced at an intensity of 70% of VO2max than 50% of VO2max. This finding implies that during prolonged exercise at a steady work rate, HR becomes increasingly less valid as a surrogate for metabolic demand of exercise. Key words: Cardiovascular drift, exercise prescription, metabolic drift

The Effects of Shoulder and Knee Angular Velocity on the Performance of a Volleyball Forearm Pass

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