Papers by Theodoros Bampouras
The Open Sports Sciences Journal, 2014
Marching with essential survival equipment is a fundamental military exercise. A consequence of t... more Marching with essential survival equipment is a fundamental military exercise. A consequence of this increased load is an increased risk of dehydration. Dehydration may have fatal consequences in a combat situation where performance must be optimal. This risk can be minimized with an understanding of the additional fluid needs of soldiers marching when loaded compared to unloaded. The aim of this study was to quantify fluid loss caused by marching with a loaded Bergen rucksack and webbing of 33.5 kg for 45 minutes when compared to unloaded carriage in eight healthy male officer cadets (age, 20.5 ± 0.9 years; body mass 80.2 ± 9.2 kg). The findings demonstrate an increased rate of sweat loss (0.6 ± 0.2 L·h -1 to 1.2 ± 0.4 L·h -1 ; p<0.001) and increased average heart rate (105.5 ± 17.7 beats·min -1 to 136.6 ± 28.3 beats·min -1 ; p<0.001) for unloaded and loaded trial respectively. Urine osmolality significantly increased pre-to postmarch (p<0.05), however there was no difference in this increase between the loaded and unloaded trial. The present study demonstrated that marching with a loaded rucksack and webbing increased sweat rate by 100% compared to the same march with no additional load. For soldiers to prevent dehydration and the potential detrimental effects on performance, fluid replacement should also be doubled when marching with loading in a temperate environment, however individual differences in sweat rate should be taken into account. © Dewhurst et al.; Licensee Bentham Open. This is an open access article licensed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/ by-nc/3.0/) which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.
International Journal of Sport Psychology , Jan 1, 2006
The aim of the present study was to evaluate the effect of practice and augmented feedback on net... more The aim of the present study was to evaluate the effect of practice and augmented feedback on netball goal-shooting performance without restricting the interaction time between the learner and the instructor. Thirty participants were randomly allocated into a control (CON), practice (being provided with KR only; PRA), or practice with augmented feedback group (being provided with KP and KR; AUG), and completed 20 netball goal-shots at pre- and post-practice testing sessions. PRA and AUG participated in 3 consecutive practice sessions, which lasted 20 minutes each. In addition, the AUG group received goal-shooting instructions (verbal cues). The AUG group showed a significantly greater improvement in scoring performance, highlighting the importance of augmented feedback in the acquisition of complex motor skills. The current study provides a bridging step between laboratory motor learning and applied research.
Journal of Strength and Conditioning Research, 2013
Esformes, JI and Bampouras, TM. Effect of back squat depth on lower-body postactivation potentiat... more Esformes, JI and Bampouras, TM. Effect of back squat depth on lower-body postactivation potentiation. J Strength Cond Res 27(11): 2997-3000, 2013-Postactivation potentiation (PAP) refers to increased muscular force generation after previous muscular activity. Various studies have used different squat variations as a PAP stimulus; however, different squat depths can have different mechanical and physiological demands that could yield different PAP levels and subsequent performance. The study aimed to compare the effects of the parallel (PS) and quarter (QS) squat on PAP. Twenty-seven, semiprofessional, male rugby union players (mean 6 SD, 18 6 2 years, 87.2 6 5.4 kg, 180.7 6 5.1 cm) performed a countermovement jump (BL-CMJ) followed by a 10-minute rest. Subsequently, they performed 3 PS or QS, at each squat's respective 3-repetition maximum load, in a randomized counterbalanced order. After a 5-minute rest, another countermovement jump (CMJ) was performed (POST-CMJ). Countermovement jump height (JH), peak power (PP), impulse (I), and flight time (FT) were recorded using a contact mat. BL-CMJ and POST-CMJ pairwise comparisons for all variables were conducted for each squat type to examine performance changes. Delta values were compared to examine whether one squat produced better CMJ results. Both squats induced PAP for all the variables (p , 0.05), although PS produced better results than QS (p , 0.05; JH, 4.6 6 2 vs. 3.5 6 2 cm; I, 15 6 6 vs. 12 6 5 N·s; PP, 285 6 109 vs. 215 6 96 W; FT, 34 6 23 vs. 26 6 11 milliseconds for PS vs. QS). This is the first study to demonstrate that different squat types can induce PAP and that PS is more beneficial for subsequent CMJ performance compared with QS. It is suggested that the deeper depth of PS, which increases gluteus maximum activation and work produced, is responsible for the increased CMJ performance. *ESs = effect sizes; CMJ = countermovement jump; QS = quarter squat; PS = parallel squat; JH = jump height; I = impulse; PP = peak power; FT = flight time. Journal of Strength and Conditioning Research the TM | www.nsca.com
Journal of Strength and Conditioning Research, 2011
Esformes, JI, Keenan, M, Moody, J, and Bampouras, TM. Effect of different types of conditioning c... more Esformes, JI, Keenan, M, Moody, J, and Bampouras, TM. Effect of different types of conditioning contraction on upper body postactivation potentiation. J Strength Cond Res 25(1): 143-148, 2011-Muscle contractions preceding an activity can result in increased force generation (postactivation potentiation [PAP]
Journal of Strength and Conditioning Research, 2010
Esformes, JI, Cameron, N, and Bampouras, TM. Postactivation potentiation following different mode... more Esformes, JI, Cameron, N, and Bampouras, TM. Postactivation potentiation following different modes of exercise. J Strength Cond Res 24 : [1911][1912][1913][1914][1915][1916] 2010-The performance characteristics of skeletal muscle are transient in nature and have been shown to be significantly affected by its contractile history, where the phenomenon of acute enhancement is termed postactivation potentiation (PAP). Acute enhancement of dynamic activity has been observed when preceded by resistance exercises; however little information exists for plyometric activity as a conditioning stimulus. In addition, no study has examined PAP effects on more than one subsequent performance trial. The purpose of the present study was to determine whether countermovement jump (CMJ) performance could be enhanced if preceded by heavyresistance exercise or by dynamic plyometric activity over 3 trials. Thirteen anaerobically trained male subjects (mean 6 SD: age, 22 6 3 years; height, 182.4 6 4.3 cm; body mass, 82.7 6 9.2 kg) performed in a counterbalanced order 3 half squats using a 3 repetition maximum loading (SQUAT), a set of 24 contacts of lower body plyometric exercises (PLYO), or a control of no activity (REST) 5 minutes before each CMJ. Three sets of each treatment and CMJ were performed in total and maximal displacement (d max ), peak power (P peak ), and peak vertical force (F peak ) were recorded, whereas rate of force development and relative force (F/body mass) were calculated for every trial. No significant differences were revealed for any of the other variables, but greater displacement was found for SQUAT compared to REST or PLYO, whereas no differences were revealed for any of the conditions for the repeated trials. Although heavy resistance-induced PAP seems to enhance jump height compared to REST or PLYO in repeated CMJ performance, it has no additional benefit on repeated trials.
BACKGROUND: Portable and cost-effective accelerometers can yield instantaneous results of force, ... more BACKGROUND: Portable and cost-effective accelerometers can yield instantaneous results of force, power, and velocity, with minimum setup time to assess muscle power. However, such devices must also produce both valid and reliable data. OBJECTIVE: The current study assessed the validity and reliability of the Myotest Pro wireless accelerometer (ACC). METHODS: Thirty physically active males performed two squat jump, on two separate sessions. The jump was recorded simultaneously by a force platform and ACC, which was attached to a barbell resting on the subjects' shoulders. Validity was determined using Pearson correlation coefficient (r) and t-test between the maximum force platform (FFP) and ACC (FACC) force. Between session reliability of FACC, power (PACC) and velocity (VACC) from the ACC were assessed with t-test, intraclass correlation coefficient (ICC), and coefficient of variation (CV). RESULTS: FACC correlated highly to FFP (r = 0.815, p < 0.05), but there was a proportionate ratio bias of 0.81. There was no difference between sessions (p > 0.05) for any variable. High ICCs were found for all variables (FACC 0.90; PACC 0.80; VACC 0.84). Low CV was found for FACC (2.1%), PACC (3.3%) and VACC (3.2%). CONCLUSIONS: ACC is a valid and reliable tool to use for assessing barbell movement, but caution in power data interpretation is needed.
The Journal of Strength & …, 2010
Esformes, JI, Cameron, N, and Bampouras, TM. Postactivation potentiation following different mode... more Esformes, JI, Cameron, N, and Bampouras, TM. Postactivation potentiation following different modes of exercise. J Strength Cond Res 24 : [1911][1912][1913][1914][1915][1916] 2010-The performance characteristics of skeletal muscle are transient in nature and have been shown to be significantly affected by its contractile history, where the phenomenon of acute enhancement is termed postactivation potentiation (PAP). Acute enhancement of dynamic activity has been observed when preceded by resistance exercises; however little information exists for plyometric activity as a conditioning stimulus. In addition, no study has examined PAP effects on more than one subsequent performance trial. The purpose of the present study was to determine whether countermovement jump (CMJ) performance could be enhanced if preceded by heavyresistance exercise or by dynamic plyometric activity over 3 trials. Thirteen anaerobically trained male subjects (mean 6 SD: age, 22 6 3 years; height, 182.4 6 4.3 cm; body mass, 82.7 6 9.2 kg) performed in a counterbalanced order 3 half squats using a 3 repetition maximum loading (SQUAT), a set of 24 contacts of lower body plyometric exercises (PLYO), or a control of no activity (REST) 5 minutes before each CMJ. Three sets of each treatment and CMJ were performed in total and maximal displacement (d max ), peak power (P peak ), and peak vertical force (F peak ) were recorded, whereas rate of force development and relative force (F/body mass) were calculated for every trial. No significant differences were revealed for any of the other variables, but greater displacement was found for SQUAT compared to REST or PLYO, whereas no differences were revealed for any of the conditions for the repeated trials. Although heavy resistance-induced PAP seems to enhance jump height compared to REST or PLYO in repeated CMJ performance, it has no additional benefit on repeated trials.
The purpose of the current study was to compare 2 water polo-specific tests-the 14 x 25-m swims (... more The purpose of the current study was to compare 2 water polo-specific tests-the 14 x 25-m swims (SWIM) and the 30-second crossbar jumps (30CJ)-with a laboratory-based test of anaerobic power, the Wingate Anaerobic Test (WAnT). Thirteen elite women's water polo players (mean +/- SD: age 22.0 +/- 4.4 years, height 168.7 +/- 7.9 cm, body mass 65.9 +/- 6.1 kg, body fat 23.6 +/- 3.5 %, maximum oxygen uptake 51.4 +/- 4.5 mlxkgxmin) participated in the study. The SWIM involved 14 repeated "all-out" sprints every 30 seconds. Swimming time was recorded, and sprint velocity, mean velocity (Vmean), and the gradient of the linear regression equation (GRADIENT) were calculated. The 30CJ involved repeated in-water water polo jumps and touching the goal crossbar with both hands. The number of touches in 30 seconds was recorded. Additionally, the subjects completed a 30-second WAnT, and mean power (Mp) and fatigue index (FI) were calculated. Kendall tau (tau) rank correlation was used to examine for correlation between ranks. Significance level was set at p <or= 0.05. No significant correlation was found between any of the measures of the WAnT and the 2 sport-specific tests. It was suggested that the WAnT may not be an appropriate evaluation tool for anaerobic power assessment of water polo players, stressing the importance of sport-specific tests.
AIM: Change of direction speed (CODS) is an important attribute for many sports and is believed t... more AIM: Change of direction speed (CODS) is an important attribute for many sports and is believed to be influenced by a variety of physical factors. However, there is a lack of consensus as to which physical attributes relate to CODS. The aim of this study was to examine the relationship of several physical attributes to CODS.METHODS: Thirty-eight subjects (mean+/-SD: age, 21.5+/-3.8 years; height, 1.77+/-0.07 m; mass, 77.5+/-13.9 kg) undertook tests of speed, CODS, strength and power. Running speed was assessed via a 25 m sprint with split times taken at 5, 20 and 25 m. CODS was assessed by a 505-test, which involves measuring the time to complete a 5 m out and back course. The strength and power tests included unilateral isokinetic concentric and eccentric knee extensor and flexor strength at 60 degrees /s and bilateral leg press, countermovement and drop jumps. Pearson's product moment correlation and co-efficients of determination were used to explore relationships amongst all variables. Multiple regression was used to determine the combined effects of significantly correlated variables on CODS.RESULTS: Stepwise multiple regression revealed that running speed explained 58% of the variance in CODS (F(1,33)=45.796, P<0.001) with the addition of eccentric knee flexor strength raising the value to 67% (F(1,32)=8.781, P=0.006).CONCLUSIONS: The results suggest that for basic improvements in CODS, athletes should seek to maximise their sprinting ability and enhance their eccentric knee flexor strength to allow effective neuromuscular control of the contact phase of the CODS task.
Muscle strength imbalances have been linked with poor agility performance and higher injury risk.... more Muscle strength imbalances have been linked with poor agility performance and higher injury risk. Isokinetic dynamometry has been used to investigate such imbalances; however, this method is impractical and inaccessible for most strength and conditioning coaches. The aim of the study was to compare isokinetic dynamometry with functional field tests for assessing bilateral strength imbalance. Thirteen male athletes from various sports (mean+/-SD: age 21+/-1.1 years, height 179.8+/-7.0 cm, body mass 80.8+/-9.7 kg) participated in the study. Knee flexor and extensor strength at 60 degrees.s(-1) was assessed for both limbs with the use of isokinetic dynamometry. Field tests involved seated unilateral leg press, horizontal hop, single-leg vertical and drop jumps. Significant differences (p<0.01) were found when comparing strength dominant (D) and nondominant (ND) limbs for all strength measures, ranging from 4.5% (hop test) to 12.4% (eccentric extension). No significant differences between the right and left limbs were found (p>0.05). No significant relationships between strength D/ND ratios of isokinetic variables and the field tests were evident (p>0.05). The findings provide support for the use of field tests to detect imbalances between lower limbs, but the ultimate choice of test used should depend on the specific strength quality that predominates in the sport.
The performance characteristics of skeletal muscle are transient in nature and have been shown to... more The performance characteristics of skeletal muscle are transient in nature and have been shown to be significantly affected by its contractile history, where the phenomenon of acute enhancement is termed postactivation potentiation (PAP). Acute enhancement of dynamic activity has been observed when preceded by resistance exercises; however little information exists for plyometric activity as a conditioning stimulus. In addition, no study has examined PAP effects on more than one subsequent performance trial. The purpose of the present study was to determine whether countermovement jump (CMJ) performance could be enhanced if preceded by heavy-resistance exercise or by dynamic plyometric activity over 3 trials. Thirteen anaerobically trained male subjects (mean +/- SD: age, 22 +/- 3 years; height, 182.4 +/- 4.3 cm; body mass, 82.7 +/- 9.2 kg) performed in a counterbalanced order 3 half squats using a 3 repetition maximum loading (SQUAT), a set of 24 contacts of lower body plyometric exercises (PLYO), or a control of no activity (REST) 5 minutes before each CMJ. Three sets of each treatment and CMJ were performed in total and maximal displacement (dmax), peak power (Ppeak), and peak vertical force (Fpeak) were recorded, whereas rate of force development and relative force (F/body mass) were calculated for every trial. No significant differences were revealed for any of the other variables, but greater displacement was found for SQUAT compared to REST or PLYO, whereas no differences were revealed for any of the conditions for the repeated trials. Although heavy resistance-induced PAP seems to enhance jump height compared to REST or PLYO in repeated CMJ performance, it has no additional benefit on repeated trials.
Muscle contractions preceding an activity can result in increased force generation (postactivatio... more Muscle contractions preceding an activity can result in increased force generation (postactivation potentiation [PAP]). Although the type of muscular contractions could affect subsequent strength and power performance, little information exists on their effects. The purpose of this study was to examine PAP effects produced by isometric (ISO), concentric (CON), eccentric (ECC), or concentric-eccentric (DYN) conditioning contractions on upper body force and power performance. Ten male, competitive rugby players (mean ± SD: age 20.4 ± 0.8 years, height 177.0 ± 8.1 cm, body mass 90.2 ± 13.8 kg) performed a ballistic bench press throw (BBPT) followed by a 10-minute rest and one of the conditioning contractions. After a 12-minute rest, the subjects performed another BBPT (post-BBPT). The conditioning contractions, applied on separate days and in counterbalanced randomized order, were a 7-second isometric barbell bench press for ISO and 1 set of 3 bench press repetitions at 3 repetition maximum for CON, ECC, and DYN (each repetition lasting 2 seconds for CON and ECC, overall execution time <7 seconds for DYN). Peak power (Ppeak), peak force (Fpeak), maximum distance (Dmax) and rate of force development (RFD) were measured using a linear position transducer. Electromyography (EMG) of the pectoralis major and triceps brachii was also recorded. The ISO produced significantly higher Ppeak (587 ± 116 and 605 ± 126 W for pre- and post-BBPT, respectively; p < 0.05). No significant differences in Ppeak were revealed for CON, ECC, and DYN (p > 0.05), and no significant differences existed in Fpeak, Dmax, and RFD for ISO, CON, ECC, and DYN (p > 0.05). Finally, EMG was not significantly different between pre- and post-BBPT for any of the conditioning contractions (p > 0.05). Isometric contractions appear to be the only conditioning contractions increasing upper body power output after long resting periods.
Voluntary activation assessment using the interpolation twitch technique (ITT) has almost invaria... more Voluntary activation assessment using the interpolation twitch technique (ITT) has almost invariably been done using maximal stimulation intensity, i.e., an intensity beyond which no additional joint moment or external force is produced by increasing further the intensity of stimulation. The aim of the study was to identify the minimum stimulation intensity at which percutaneous ITT yields valid results. Maximal stimulation intensity and the force produced at that intensity were identified for the quadriceps muscle using percutaneous electrodes in eight active men. The stimulation intensities producing 10-90% (in 10% increments) of that force were determined and subsequently applied during isometric contractions at 90% of maximum voluntary contraction (MVC) via twitch doublets. Muscle activation was calculated with the ITT and pain scores were obtained for each stimulation intensity and compared to the respective values at maximum stimulation intensity. Muscle activation at maximal stimulation intensity was 91.6 (2.5)%. The lowest stimulation intensity yielding comparable muscle activation results to maximal stimulation was 50% (88.8 (3.9)%, p < 0.05). Pain score at maximal stimulation intensity was 6.6 (1.5) cm and it was significantly reduced at 60% stimulation intensity (3.7 (1.5) cm, p < 0.05) compared to maximal stimulation intensity. Submaximal stimulation can produce valid ITT results while reducing the discomfort obtained by the subjects, widening the assessment of ITT to situations where discomfort may otherwise impede maximal electrostimulation.Copyright © 2012 Elsevier Ltd. All rights reserved.
Limited research examining the effect of taurine (TA) ingestion on human exercise performance exi... more Limited research examining the effect of taurine (TA) ingestion on human exercise performance exists. The aim of this study was to investigate the effect of acute ingestion of 1,000 mg of TA on maximal 3-km time trial (3KTT) performance in trained middle-distance runners (MDR). Eight male MDR (mean ± SD: age 19.9 ± 1.2 years, body mass 69.4 ± 6.6 kg, height 180.5 ± 7.5 cm, 800 m personal best time 121.0 ± 5.3 s) completed TA and placebo (PL) trials 1 week apart in a double-blind, randomised, crossover designed study. Participants consumed TA or PL in capsule form on arrival at the laboratory followed by a 2-h ingestion period. At the end of the ingestion period, participants commenced a maximal simulated 3KTT on a treadmill. Capillary blood lactate was measured pre- and post-3KTT. Expired gas, heart rate (HR), ratings of perceived exertion (RPE), and split times were measured at 500-m intervals during the 3KTT. Ingestion of TA significantly improved 3KTT performance (TA 646.6 ± 52.8 s and PL 658.5 ± 58.2 s) (p = 0.013) equating to a 1.7 % improvement (range 0.34-4.24 %). Relative oxygen uptake, HR, RPE and blood lactate did not differ between conditions (p = 0.803, 0.364, 0.760 and 0.302, respectively). Magnitude-based inference results assessing the likeliness of a beneficial influence of TA were 99.3 %. However, the mechanism responsible for this improved performance is unclear. TA's potential influence on exercise metabolism may involve interaction with the muscle membrane, the coordination or the force production capability of involved muscles. Further research employing more invasive techniques may elucidate TA's role in improving maximal endurance performance.
ABSTRACT: Postactivation potentiation (PAP) refers to increased muscular force generation followi... more ABSTRACT: Postactivation potentiation (PAP) refers to increased muscular force generation following previous muscular activity. Various studies have used different squat variations as a PAP stimulus; however, different squat depths can have different mechanical and physiological demands that could yield different PAP levels and subsequent performance. The study aimed to compare the effects of the parallel (PS) and quarter (QS) squat on PAP. Twenty seven semi-professional male rugby union players (mean±SD, 18±2 years, 87.2±5.4 kg, 180.7±5.1 cm) performed a countermovement jump (BL-CMJ) followed by a 10-min rest. Subsequently, they performed 3 PS or QS, at each squat's respective 3 repetition maximum load, in a randomised, counterbalanced order. Following a 5-min rest, another CMJ was performed (POST-CMJ). CMJ jump height (JH), peak power (PP), impulse (I), and flight time (FT) were recorded using a contact mat. BL-CMJ and POST-CMJ pairwise comparisons for all variables were conducted for each squat type to examine performance changes. Delta values were compared to examine whether one squat produced better CMJ results. Both squats induced PAP for all the variables (P<0.05), while PS produced better results than QS (P<0.05; JH, 4.6±2 v 3.5±2 cm; I, 15±6 v 12±5 N·s; PP, 285±109 v 215±96 W; FT, 34±23 v 26±11 ms for PS v QS). This is the first study to demonstrate that different squat types can induce PAP and that PS is more beneficial for subsequent CMJ performance compared to QS. It is suggested that the deeper depth of PS, which increases gluteus maximum activation and work produced, is responsible for the increased CMJ performance.
The effects of long term participation in Scottish country dance (SCD) on body composition, funct... more The effects of long term participation in Scottish country dance (SCD) on body composition, functional ability, and balance in healthy older females were examined. Participants were grouped into dancers and physically active non-dancers (60-70 and 70-80 year olds for both groups). Physical activity, body composition (body mass index, skinfold thickness, waist-to-hip ratio), functional ability (6-minute walk distance, 6-metre walk time, 8-foot up-and-go time, lower body flexibility, shoulder flexibility) and static balance were measured. Younger dancers and physically active non-dancers had similar 6-minute walk distance, 6-metre walk time and 8-foot up-and-go time results. However, while older dancers performed similarly to younger dancers, older physically active non-dancers performed poorer than their younger counterparts (p<0.05). Body composition and static balance were the same for all groups. Regular physical activity can maintain body composition and postural stability with advancing age, however SCD can delay the effects of ageing on locomotion-related functional abilities.
British Journal of Sports Medicine, 2010
BACKGROUND: Portable and cost-effective accelerometers can yield instantaneous results of force, ... more BACKGROUND: Portable and cost-effective accelerometers can yield instantaneous results of force, power, and velocity, with minimum set-up time to assess muscle power. However, such devices must also produce both valid and reliable data. OBJECTIVE: The current study assessed the validity and reliability of the Myotest Pro wireless accelerometer (ACC). METHODS: Thirty physically active males performed two squat jump, on two separate sessions. The jump was recorded simultaneously by a force platform and ACC, which was attached to a barbell resting on the subjects' shoulders. Validity was determined using Pearson correlation coefficient (r) and t-test between the maximum force platform (FFP) and ACC (FACC) force. Between session reliability of FACC, power (PACC) and velocity (VACC) from the ACC were assessed with t-test, intraclass correlation coefficient (ICC), and coefficient of variation (CV). RESULTS: FACC correlated highly to FFP (r = 0.815, p < 0.05), but there was a proportionate ratio bias of 0.81. There was no difference between sessions (p > 0.05) for any variable. High ICCs were found for all variables (FACC 0.90; PACC 0.80; VACC 0.84). Low CV was found for FACC (2.1%), PACC (3.3%) and VACC (3.2%). CONCLUSIONS: ACC is a valid and reliable tool to use for assessing barbell movement, but caution in power data interpretation is needed.
British Journal of Sports Medicine, 2010
Lower limb strength ratios are important in assessing muscular imbalances. Typically, these ratio... more Lower limb strength ratios are important in assessing muscular imbalances. Typically, these ratios are derived from assessment of explosive, maximum effort activities. Such assessment can be functional or isokinetic. The single-effort nature of these assessments does not provide information on imbalance changes after muscular contractions. Any such change could indicate an increased risk of injury after a period of activity, thus raising questions as to the correct procedure of muscle imbalance assessment. Therefore, the aim of the current study was to assess muscle imbalances over maximum effort repeated cycling sprints. Seventeen healthy, physically active young adults (females: n=4, height 1.62±0.03 m, body mass 68.0±6.5 kg; males: n=13, height 1.80±0.06 m, body mass 80.5±13.8 kg) performed five 6-s sprints with 24-s rest interval on a Lode Excalibur bike with torque and power data recorded for each leg. Average, average maximum (average of maximum from each sprint) and peak torque (TAv, TAvM and TP respectively) and power (PAv, PAvM and PP respectively) were obtained for each leg. Ratios of these variables were calculated as [Stronger leg−Weaker legAverage of two legs×100]. Wilcoxon's test revealed a significantly stronger leg (p<0.05) for all torque and power variables. Friedman's test indicated a significant ratio increase between TAv (11.7±6.8%) and TAvM (4.6±3.0%, p=0.001) and TP (4.1±3.5%, p=0.001), as well as between PAv (8.8±5.0%) and PAvM (4.5±2.9%, p=0.003) and PP (4.2±2.6, p=0.003%) but not between TAvM and TP (p=0.421) or PAvM and PP (p=0.981). The results indicate that high-intensity activity increases lower limb strength imbalance, resulting in different ratios. The authors posit that muscle imbalance assessment activities conducted at rested state may not accurately reflect the true strength difference between limbs, leading to inaccurate training or rehabilitation advice.
Journal of Biomechanics, 2006
Strength and Conditioning Journal, 2007
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Papers by Theodoros Bampouras