Journal of strength and conditioning research / National Strength & Conditioning Association, Jan 10, 2015
The purposes of this study were to measure the acute effects of knee wraps on knee and hip joint ... more The purposes of this study were to measure the acute effects of knee wraps on knee and hip joint kinematics, dynamic muscle activation from the vastus lateralis and gluteus maximus, and rating of perceived exertion (RPE) during the back squat exercise at two different intensities. Fourteen resistance-trained men (age: 24±4 years, height: 176±6cm, body mass: 81±11kg, back squat 1RM: 107±30kg, 3±1 years of back squat experience) performed one set of 3 repetitions under four different conditions, to a depth of ∼90 degrees of knee joint flexion, and in random order: with knee wraps at 60% 1RM (KW60), with knee wraps at 90% 1RM (KW90), without knee wraps at 60% 1RM (NW60), and without knee wraps at 90% 1RM (NW90). The dependent variables obtained were vertical and horizontal bar displacement, peak joint angle in the sagittal plane (hip and knee joints), concentric and eccentric muscle activation (by integrated electromyography) from the vastus lateralis (VL) and gluteus maximus (GM), and...
Journal of strength and conditioning research / National Strength & Conditioning Association, Jan 10, 2015
The purposes of this study were to measure the acute effects of knee wraps on knee and hip joint ... more The purposes of this study were to measure the acute effects of knee wraps on knee and hip joint kinematics, dynamic muscle activation from the vastus lateralis and gluteus maximus, and rating of perceived exertion (RPE) during the back squat exercise at two different intensities. Fourteen resistance-trained men (age: 24±4 years, height: 176±6cm, body mass: 81±11kg, back squat 1RM: 107±30kg, 3±1 years of back squat experience) performed one set of 3 repetitions under four different conditions, to a depth of ∼90 degrees of knee joint flexion, and in random order: with knee wraps at 60% 1RM (KW60), with knee wraps at 90% 1RM (KW90), without knee wraps at 60% 1RM (NW60), and without knee wraps at 90% 1RM (NW90). The dependent variables obtained were vertical and horizontal bar displacement, peak joint angle in the sagittal plane (hip and knee joints), concentric and eccentric muscle activation (by integrated electromyography) from the vastus lateralis (VL) and gluteus maximus (GM), and...
Journal of strength and conditioning research / National Strength & Conditioning Association, Jan 10, 2015
The purposes of this study were to measure the acute effects of knee wraps on knee and hip joint ... more The purposes of this study were to measure the acute effects of knee wraps on knee and hip joint kinematics, dynamic muscle activation from the vastus lateralis and gluteus maximus, and rating of perceived exertion (RPE) during the back squat exercise at two different intensities. Fourteen resistance-trained men (age: 24±4 years, height: 176±6cm, body mass: 81±11kg, back squat 1RM: 107±30kg, 3±1 years of back squat experience) performed one set of 3 repetitions under four different conditions, to a depth of ∼90 degrees of knee joint flexion, and in random order: with knee wraps at 60% 1RM (KW60), with knee wraps at 90% 1RM (KW90), without knee wraps at 60% 1RM (NW60), and without knee wraps at 90% 1RM (NW90). The dependent variables obtained were vertical and horizontal bar displacement, peak joint angle in the sagittal plane (hip and knee joints), concentric and eccentric muscle activation (by integrated electromyography) from the vastus lateralis (VL) and gluteus maximus (GM), and...
BACKGROUND: The isokinetic hamstrings to quadriceps (H:Q) dynamic control ratio (DCR) is frequent... more BACKGROUND: The isokinetic hamstrings to quadriceps (H:Q) dynamic control ratio (DCR) is frequently used to assess muscle imbalances and to screen for potential risks of knee injuries in sports. OBJECTIVE: To investigate the correlation between knee conventional ratio (CR) and DCR in elite soccer players and check for a possible relationship. A positive correlation would indicate that the CR could predict DCR. METHODS: One hundred and thirteen Brazilian elite soccer players (25.2 ± 5.3 yrs) performed maximal dominant and non-dominant knee concentric (CON) and eccentric (ECC) strength tests at 60 • /s on an isokinetic dynamometer in order to calculate CR and DCR. RESULTS: A significant positive correlation between ratios was found for the dominant and non-dominant knees (r = 0.54 and 0.62; p < 0.001 which translated into low R 2 values of 0.29 and 0.39, respectively. CONCLUSION: This suggests that the CR may not replace the DCR and is thus of a limited clinical value in assessing knee muscles imbalance. On the other hand, the paper presents for the first time a robust reference frame for the isokinetic strength and related ratios of the two major knee muscles in soccer players.
Journal of strength and conditioning research / National Strength & Conditioning Association, Jan 10, 2015
The purposes of this study were to measure the acute effects of knee wraps on knee and hip joint ... more The purposes of this study were to measure the acute effects of knee wraps on knee and hip joint kinematics, dynamic muscle activation from the vastus lateralis and gluteus maximus, and rating of perceived exertion (RPE) during the back squat exercise at two different intensities. Fourteen resistance-trained men (age: 24±4 years, height: 176±6cm, body mass: 81±11kg, back squat 1RM: 107±30kg, 3±1 years of back squat experience) performed one set of 3 repetitions under four different conditions, to a depth of ∼90 degrees of knee joint flexion, and in random order: with knee wraps at 60% 1RM (KW60), with knee wraps at 90% 1RM (KW90), without knee wraps at 60% 1RM (NW60), and without knee wraps at 90% 1RM (NW90). The dependent variables obtained were vertical and horizontal bar displacement, peak joint angle in the sagittal plane (hip and knee joints), concentric and eccentric muscle activation (by integrated electromyography) from the vastus lateralis (VL) and gluteus maximus (GM), and...
Journal of strength and conditioning research / National Strength & Conditioning Association, Jan 10, 2015
The purposes of this study were to measure the acute effects of knee wraps on knee and hip joint ... more The purposes of this study were to measure the acute effects of knee wraps on knee and hip joint kinematics, dynamic muscle activation from the vastus lateralis and gluteus maximus, and rating of perceived exertion (RPE) during the back squat exercise at two different intensities. Fourteen resistance-trained men (age: 24±4 years, height: 176±6cm, body mass: 81±11kg, back squat 1RM: 107±30kg, 3±1 years of back squat experience) performed one set of 3 repetitions under four different conditions, to a depth of ∼90 degrees of knee joint flexion, and in random order: with knee wraps at 60% 1RM (KW60), with knee wraps at 90% 1RM (KW90), without knee wraps at 60% 1RM (NW60), and without knee wraps at 90% 1RM (NW90). The dependent variables obtained were vertical and horizontal bar displacement, peak joint angle in the sagittal plane (hip and knee joints), concentric and eccentric muscle activation (by integrated electromyography) from the vastus lateralis (VL) and gluteus maximus (GM), and...
Journal of strength and conditioning research / National Strength & Conditioning Association, Jan 10, 2015
The purposes of this study were to measure the acute effects of knee wraps on knee and hip joint ... more The purposes of this study were to measure the acute effects of knee wraps on knee and hip joint kinematics, dynamic muscle activation from the vastus lateralis and gluteus maximus, and rating of perceived exertion (RPE) during the back squat exercise at two different intensities. Fourteen resistance-trained men (age: 24±4 years, height: 176±6cm, body mass: 81±11kg, back squat 1RM: 107±30kg, 3±1 years of back squat experience) performed one set of 3 repetitions under four different conditions, to a depth of ∼90 degrees of knee joint flexion, and in random order: with knee wraps at 60% 1RM (KW60), with knee wraps at 90% 1RM (KW90), without knee wraps at 60% 1RM (NW60), and without knee wraps at 90% 1RM (NW90). The dependent variables obtained were vertical and horizontal bar displacement, peak joint angle in the sagittal plane (hip and knee joints), concentric and eccentric muscle activation (by integrated electromyography) from the vastus lateralis (VL) and gluteus maximus (GM), and...
BACKGROUND: The isokinetic hamstrings to quadriceps (H:Q) dynamic control ratio (DCR) is frequent... more BACKGROUND: The isokinetic hamstrings to quadriceps (H:Q) dynamic control ratio (DCR) is frequently used to assess muscle imbalances and to screen for potential risks of knee injuries in sports. OBJECTIVE: To investigate the correlation between knee conventional ratio (CR) and DCR in elite soccer players and check for a possible relationship. A positive correlation would indicate that the CR could predict DCR. METHODS: One hundred and thirteen Brazilian elite soccer players (25.2 ± 5.3 yrs) performed maximal dominant and non-dominant knee concentric (CON) and eccentric (ECC) strength tests at 60 • /s on an isokinetic dynamometer in order to calculate CR and DCR. RESULTS: A significant positive correlation between ratios was found for the dominant and non-dominant knees (r = 0.54 and 0.62; p < 0.001 which translated into low R 2 values of 0.29 and 0.39, respectively. CONCLUSION: This suggests that the CR may not replace the DCR and is thus of a limited clinical value in assessing knee muscles imbalance. On the other hand, the paper presents for the first time a robust reference frame for the isokinetic strength and related ratios of the two major knee muscles in soccer players.
Purpose: The purpose of this study was to investigate the effects of general and specific warm-up... more Purpose: The purpose of this study was to investigate the effects of general and specific warm-up protocols on rate of force development (RFD), relative RFD (rRFD), ground reaction force (GRF) and relative ground reaction force (rGRF) during an isometric mid-thigh pull (IMTP), after WBV exposure. Methods: Fifteen healthy recreationally trained males (age: 24.1 ± 2.3 yrs, height: 72.9 ± 7.8 cm; mass: 86.9 ± 8.3) completed five protocols: baseline, isometric vibration (iVib), isometric no vibration (iNV), dynamic vibration (dVib) and dynamic no vibration (dNV). The baseline was completed without any warm-up prior to the IMTP. The intervention protocols had the same prescription of 4 sets of 30-second bouts of quarter squats (dynamic [DQS] and isometric [IQS]) on the WBV platform with or without vibration. Following a one-minute rest period after each protocol, participants completed three maximal IMTPs. Results: Repeated measures ANOVA with a Bonferroni post hoc demonstrated that RFD in dNV (7657.8 ± 2292.5 N/s) was significantly greater than iVib (7156.4 ± 2170.0 N/s). However, the other experimental trials for RFD demonstrated no significant differences (p>0.05). There were also no significant differences for rRFD, GRF or rGRF between protocols. Conclusion: These results demonstrate that a dynamic warm-up without WBV elicits greater RFD than an isometric warm-up with WBV prior to a maximal isometric exercise. Further research needs to be investigated utilizing dynamic and isometric warm-ups in conjunction with WBV and power output.
Punching is integral to success in combat sports, making it a frequent activity during practice/t... more Punching is integral to success in combat sports, making it a frequent activity during practice/training. Improving safety of this activity benefits both the athlete and training partners. This study was designed to 1) test the precision and reliability of a commercially available striking device and 2) assess the influence of a novel padded hand wrap on punching force in elite and untrained punchers. Fourteen male professional boxers and mixed martial artists (PRO; age=29.2±5.6y; height=180.3±9.0cm; mass=87.1±17.9kg, winning %=73.8±13.8%, number of victories via knockout/technical knockout=35.6± 21.9%) and 24 untrained male punchers (UNT; 27.6±6.9y, 177.6±18.3cm, 84.3±16.9kg) wore a standardized boxing glove and performed 20 maximal punches (4 sets of 5) into a device designed to measure punching force. All participants performed, in a counterbalanced order, 2 sets of 5 with a standardized hand wrap and 2 sets of 5 with the same wrap plus an additional 1.2cm thick cylinder 4g foam-like pad (WRAP) placed over the knuckles. PRO produced significantly more punching force than UNT, regardless of condition. Punching force was lower by 12.6% (p<0.05) for PRO and 8.9% (p<0.05) for UNT with WRAP (compared to no WRAP). These findings suggest WRAP significantly reduces punching force, which may be important for long-term safety of the puncher’s hand and/or the person receiving the strike
Background: The drum set involves dynamic movement of all four limbs. Motor control studies have ... more Background: The drum set involves dynamic movement of all four limbs. Motor control studies have been done on drum set playing, yet not much is known about the physiological responses to this activity. Even less is known about heavy metal drumming. Aims: The purpose of this study was to determine metabolic responses and demands of heavy metal drumming. Methods: Five semi-professional male drummers (mean ± SD age = 27.4 ± 2.6 y, height = 177.2 ± 3.8 cm, body mass = 85.1 ± 17.8 kg) performed four prescribed and four self-selected heavy metal songs. Oxygen consumption (VO2), minute ventilation (VE) and respiratory exchange ratio (RER) were measured using a metabolic cart. Heart rate (HR) was measured using a heart rate monitor. VO2max was determined using a graded cycle ergometer test. Results: The results indicated a metabolic cost of 6.3 ± 1.4 METs and heart rate of 145.1 ± 15.7 beats·min-1 (75.4 ± 8.3% of age-predicted HRmax). VO2 peak values reached approximately 90% of the drummer's VO2max when performing at the fastest speeds. According to these results, heavy metal drumming may be considered vigorous intensity activity (≥ 6.0 METs). The relative VO2max of 40.2 ± 9.5 mL·kg·min-1 leads to an aerobic fitness classification of " average " for adult males. Conclusions: The metabolic demands required during heavy metal drumming meet the American College of Sports Medicine guidelines for the development of health related fitness.
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Papers by Lee E Brown