Long-term Return to Sports After Anterior Cruciate Ligament Injury: Reconstruction vs No Reconstruction-A Comparison of 2 Case Series.

BACKGROUND: Reconstruction is considered to provide the best opportunity for return to sports (RTS) after anterior cruciate ligament (ACL) rupture. However, recent studies report that <50% of athletes return to preinjury sporting levels and that RTS rates at 1 year after injury are the same for athletes undergoing reconstruction and nonoperative management. Long-term studies are essential to confirm these findings and guide decisions regarding surgery. PURPOSE: First, to compare long-term sports participation after ACL reconstruction and nonreconstruction and, second, to relate RTS level to strength and stability. STUDY DESIGN: Cohort study; Level of evidence, 3. METHOD: Patients with ACL deficiency (n = 101) who were referred for physical therapy at the time of diagnosis were followed long term: 56 were treated surgically 2.5 years (interquartile range [IQR], 1-4) after injury and 45 were treated nonoperatively. At long-term follow-up, the reconstructed group was at 9 years (IQR, 7-11) after injury and aged 33.3 ± 6.2 years (mean ± SD, 70% male; 61% meniscal injury), and the nonreconstructed group was at 11 years (IQR, 7-14) after injury and aged 38.7 ± 8.3 years (67% male; 58% meniscal injury). Measures of objective stability, subjective stability, and quadriceps/hamstring strength were compared between groups using independent-samples t tests. Current RTS level, scored on a 6-point scale, was compared between groups using chi-square tests. Spearman rho correlated RTS with outcome measures. RESULTS: Of the total group of patients, 96% with reconstruction and 93% without continued to play sports. In the reconstructed and nonreconstructed groups, 4% and 7% did not RTS, and 8% and 17% returned to safe sports, respectively: 13% and 12% to running, 20% and 26% to sports involving limited twisting, 12% and 24% to recreational pivoting sports, and 43% and 14% to competitive pivoting sports. The only significant difference was in return to competitive pivoting sports (P = .003). Five patients with reconstruction ruptured the contralateral ACL, and 1 ruptured his graft. Most patients treated nonoperatively modified their sports participation. Their RTS levels correlated significantly with quadriceps strength (r = 0.65; P < .001), hamstring strength (r = 0.721; P < .001), and subjective stability (r = 0.405; P = .01). CONCLUSION: Surgically treated patients returned to competitive pivoting sports at 3 times the rate of those managed nonoperatively, confirming that reconstruction provides the best opportunity for continued participation in competitive pivoting sports. Regardless of grouping, RTS correlated with modifiable factors, including strength and stability. Higher rates of subsequent injuries observed after reconstruction may result from increased participation in competitive pivoting sports.

Factors that influence ground reaction force profiles during counter movement jumping.

BAKGROUND: The purpose of this study was to examine how hip, knee and ankle kinetics and kinematics influence effective impulse production during countermovement jumps. METHODS: Eighteen semi-professional soccer players (22.8±2.2 years) volunteered to participate in the study. Participants completed three maximal countermovement jumps on two force platforms (1000 Hz) that were linked to a nine camera infrared motion capture system (500 Hz). RESULTS: Kinetic and kinematic data revealed jumpers who fail to achieve uniform ground reaction force curves that result in optimal impulse production during their jump always display hip adduction and or hip internal rotation during the concentric phase of the countermovement jump. The variation of hip adduction and or internal rotation likely represents failed joint transition during the concentric phase of the countermovement jump and appears to account for a non-uniform force trace seen in these jumpers. CONCLUSIONS: The findings suggest rehabilitation and conditioning exercises for injury prevention and performance may benefit from targeting frontal and transverse plane movement.

Changes in sleep quantity and efficiency in professional rugby union players during home-based training and match play.

BACKGROUND: Adequate sleep is paramount to athlete recovery and performance, however little is known about the typical sleep patterns of professional rugby union players during home based training and match play in the competitive season. The aim of the present study was to monitor changes in sleep quantity and efficiency of elite male rugby union players over a twelve-night period, which included training and two competitive matches. METHODS: A total of ten elite male rugby union players from a selected team, participated in the study. Athletes' sleep quantity and efficiency was monitored over a twelve-night period using the BodyMedia SenseWear units (BSU). RESULTS: There was a significant difference in sleep quantity (P<0.05) on game nights compared to non-game night, with players sleeping less on game nights. Time to sleep on game nights was also significantly (P<0.05) later than non-game nights. There was no significant difference in sleep efficiency or time at wake over the twelve-night period. Sleep efficiency is defined as a percentage score calculated by incorporating movement and physiological measures over the sleep duration as determined by the BSU. Also there was no significant difference between sleep parameters on the game nights. The findings show players have significantly (P<0.05) reduced sleep following a home game, which is of concern considering the established negative influence of sleep deprivation on cognitive and physical performance. CONCLUSIONS: This data may assist coaching, medical and performance staff to develop and implement team and individualised sleep monitoring regimes to optimise training and on-field performance.

Performance analysis of professional, semiprofessional, and junior elite rugby league match-play using global positioning systems.

The aim of the present study was to examine the positional differences in physical performance measures of professional, semiprofessional, and junior elite rugby league match-play using portable Global Positioning Systems (GPSs). Twelve professional, 12 semiprofessional, and 18 junior elite male rugby league players were monitored during 5 regular-season competition matches using portable GPS software. The mean total distance traveled during professional (8,371 ± 897 m) and semiprofessional (7,277 ± 734 m) match-play was significantly (p < 0.05) greater than that traveled during elite junior (4,646 ± 978 m) match-play. Position-specific total distance traveled and distance traveled per minute of playing time were significantly (p < 0.05) less for junior elite backs (5,768 ± 765 m; 74 ± 11 m·min) and forwards (4,774 ± 564 m; 82 ± 5 m·min) in comparison to those in professional (backs: 8,158 ± 673 m; 101 ± 8 m·min and forwards: 8,442 ± 812 m; 98 ± 12 m·min) and semiprofessional (backs: 7,505 ± 765 m; 94 ± 8 m·min and forwards: 6,701 ± 678 m; 89 ± 8 m·min) match-play. Maximum running speed, maximum sprints, and total sprint distance traveled by professional players were all significantly (p < 0.05) greater than those traveled by junior elite players but not semiprofessional players during match-play. Professional backs and forwards performed significantly (p < 0.05) more maximum sprints and traveled greater total distance during match-play in comparison to semiprofessional and junior elite players. The present findings demonstrate minimal differences in the physical performance measures of professional and semiprofessional rugby league match-play. The position-specific performance characteristics of junior elite match-play indicate that current junior elite player-development pathways may not provide adequate preparation for players transitioning into professional competition.

Neuromuscular responses to impact and collision during elite rugby league match play.

The purpose of this study was to investigate the relationship between the prematch and short-term postmatch neuromuscular responses to the intensity, number, and distribution of impacts associated with collisions during elite Rugby League match play. Twenty-two elite male Rugby League players were monitored during 8 regular season competition matches using portable global positioning system (GPS) technology. The intensity, number, and distribution of impact forces experienced by players during match play were recorded using integrated accelerometry. Peak rate of force development (PRFD), peak power (PP), and peak force (PF) were measured during a countermovement jump on a force plate 24 hours prematch, 30 minutes prematch, 30 minutes postmatch and then at 24-hour intervals for a period of 5 days postmatch. The change in the dependent variables at each sample collection time was compared with that at 24 hours prematch and 30-minute prematch measures. There were significant (p < 0.05) decreases in PRFD and PP up to 24 hours postmatch with PF significantly (p < 0.05) being decreased 30 minutes postmatch. Significant (p < 0.05) correlations were found between the total number of impacts and PRFD and PP 30 minutes postmatch. Impact zones 4 (7.1-8.0 G), 5 (>8.1-10.0 G), and 6 (>10.1 G) were significantly (p < 0.05) correlated to PRFD and PP 30 minutes postmatch with the number of zone 5 and 6 impacts significantly (p < 0.05) correlated to PRFD and PP 24 hours postmatch. Elite Rugby League match play resulted in significant neuromuscular fatigue and was highly dependent on the number of heavy collisions >7.1G. Results demonstrate that neuromuscular function is compromised for up to 48 hours postmatch indicating that at least 2 days of modified activity is required to achieve full neuromuscular recovery after elite Rugby League match play. Position-specific demands on energy systems and the influence of repeated blunt force trauma during collisions during elite Rugby League match play should be considered when planning postmatch recovery protocols and training activities to optimize subsequent performance.

The hormonal response of older men to sub-maximum aerobic exercise: the effect of training and detraining.

The hormonal response of 32 older men (70-80years) to a bout of sub-maximum aerobic exercise was examined before, after 16weeks of resistance or aerobic training and again after 4weeks of detraining. Blood samples were obtained at rest and immediately post sub-maximum exercise (30min @ 70% VO(2) max) to determine the concentrations of growth hormone (GH), insulin-like growth factor-1 (IGF-1), testosterone (Test), sex hormone-binding globulin (SHBG) and the calculation of free testosterone (FT). Both training groups had significant increases in leg strength and VO(2) max after 16weeks training but leg strength and VO(2) max returned to pre-training levels in the aerobic training and resistance training groups, respectively. During the 20week study there was no change in resting concentrations of any hormones among the three groups. There was no increase in GH, IGF-1 or SHBG immediately post sub-maximum exercise in any of the groups before training, after 16weeks training or after 4weeks detraining. Testosterone and FT increased immediately post sub-maximum exercise within all groups before training, after 16weeks training and after 4weeks detraining with the increase in Test and FT higher after 16weeks of resistance training compared to before training and after 4weeks detraining within the resistance training group. The increased responsiveness of Test and FT after 16weeks of resistance training was lost after 4weeks of detraining. Our results indicate that some physiological and hormonal adaptations gained after 16weeks training are lost after only 4weeks detraining.

Do compression garments enhance the active recovery process after high-intensity running?

Lovell, DI, Mason, DG, Delphinus, EM, and McLellan, CP. Do compression garments enhance the active recovery process after high-intensity running? J Strength Cond Res 25(12): 3264-3268, 2011-This study examined the effect of wearing waist-to-ankle compression garments (CGs) on active recovery after moderate- and high-intensity submaximal treadmill running. Twenty-five male semiprofessional rugby league players performed two 30-minute treadmill runs comprising of six 5-minute stages at 6 km·h, 10 km·h, approximately 85% VO(2)max, 6 km·h as a recovery stage followed by approximately 85% VO(2)max and 6 km·h wearing either CGs or regular running shorts in a randomized counterbalanced order with each person acting as his own control. All stages were followed by 30 seconds of rest during which a blood sample was collected to determine blood pH and blood lactate concentration [La]. Expired gases and heart rate (HR) were measured during the submaximal treadmill tests to determine metabolic variables with the average of the last 2 minutes used for data analysis. The HR and [La] were lower (p ≤ 0.05) after the first and second 6 km·h recovery bouts when wearing CGs compared with when wearing running shorts. The respiratory exchange ratio (RER) was higher and [La] lower (p ≤ 0.05) after the 10 km·h stage, and only RER was higher after both 85% VO(2)max stages when wearing CGs compared with when wearing running shorts. There was no difference in blood pH at any exercise stage when wearing the CGs and running shorts. The results of this study indicate that the wearing of CGs may augment the active recovery process in reducing [La] and HR after high-intensity exercise but not effect blood pH. The ability to reduce [La] and HR has important consequences for many sports that are intermittent in nature and consist of repeated bouts of high-intensity exercise interspersed with periods of low-intensity exercise or recovery.

A comparison of asynchronous and synchronous arm cranking during the Wingate test.

PURPOSE: The aim of this study was to compare asynchronous (ASY) arm cranking (cranks at 180° relative to each other) with synchronous (SYN) arm cranking (parallel crank setting) during the 30 s Wingate anaerobic test. METHODS: Thirty two physically active men (aged 22.1 ± 2.4 y) completed two Wingate tests (one ASY and one SYN) separated by 4 d in a randomized counterbalanced order. The Wingate tests were completed on a modified electromagnetically braked cycle ergometer. Performance measures assessed during the two tests include peak power, mean power, minimum power, time to peak power, rate to fatigue and maximum cadence (RPMmax). Blood lactate concentration was also measured before and 5 min after the tests. RESULTS: Peak and mean power (both absolute and relative to body weight) during SYN arm cranking were significantly (p < 0.001) less than during ASY arm cranking. Rate to fatigue and RPMmax were also significantly (p = 0.012) lower during SYN arm cranking compared with ASY arm cranking. No significant difference was found between test conditions for minimum power, time to peak power or blood lactate concentration. CONCLUSIONS: These findings demonstrate that ASY arm cranking results in higher peak and mean anaerobic power compared with SYN arm cranking during the Wingate test. Therefore, an ASY arm crank configuration should be used to assess anaerobic power in most individuals although specific population groups may require further testing.

Biochemical and endocrine responses to impact and collision during elite Rugby League match play.

The purpose of this study was to investigate the relationship between the prematch and short-term postmatch biochemical and endocrine responses to the intensity, number, and distribution of impacts associated with collisions during elite Rugby League match play. Seventeen elite male Rugby League players each provided blood and saliva samples 24 hours prematch, 30 minutes prematch, 30 minutes postmatch, and then at 24-hour intervals for a period of 5 days postmatch to determine plasma creatine kinase concentration ([CK]) and salivary cortisol concentration ([sCort]). The intensity, number, and distribution of impact forces experienced by players during match play were recorded using portable global positioning systems (GPSs). The change in the dependent variables at each sample collection time was compared to 24 hours prematch and 30-minute prematch measures. The [CK] and [sCort] increased significantly (p < 0.05) during match play. Significant correlations (p < 0.05) were observed between the number of hit-ups and peak [CK] 24 hours postmatch, 48 hours postmatch, and 72 hours postmatch (p < 0.05). The number of impacts recorded in zone 5 (8.1-10.0G) and zone 6 (>10.1G) during match play was significantly correlated (p < 0.05) to [CK] 30 minutes postmatch, 24 hours post, 48 hours post, and 72 hours postmatch. The GPS was able to provide data on the intensity, number, and distribution of impacts resulting from collisions during match play. Elite Rugby League match play resulted in significant skeletal muscle damage and was highly dependent on the number of heavy collisions >8.1G. [CK] remained elevated 120 hours postmatch identifying that at least 5 days modified activity is required to achieve full recovery after elite Rugby League match play.

Performance analysis of elite Rugby League match play using global positioning systems.

The aim of this study was (a) to examine the physiological demands of competitive Rugby League match play using portable Global Positioning Systems (GPSs) to monitor players' movement patterns and heart rate (HR) and (b) examine positional comparisons to determine if players' physiological requirements are influenced by their playing position during Rugby League match play. Twenty-two elite male Rugby League players were monitored during 5 regular season competition matches using portable GPS software. There was no difference in the total distance traveled between backs (5,573 ± 1,128 m) and forwards (4,982 ± 1,185 m) during match play. Backs and forwards had an average HR of approximately 80% of their maximum (162 ± 11 and 165 ± 12 b · min(-1), respectively) throughout each match. Backs achieved greater maximum running speed (8.6 ± 0.7 m · s(-1)), completed a greater number of sprints (18 ± 6), had less time between sprints (3.2 ± 1.1 minutes), achieved a greater total duration of sprinting (44.7 ± 9.1 seconds), and covered more distance sprinting (321 ± 74 m) than forwards did (6.8 ± 0.7 m · s(-1), 11 ± 5, 5.2 ± 2.2 minutes, 25.8 ± 9.2 seconds, and 153 ± 38 m, respectively). The GPS successfully provided real-time feedback to identify significant positional differences in distances covered, running speed characteristics, and the physiological demands of competitive Rugby League match play.

The blood pressure response of older men to maximum and sub-maximum strength testing.

Strength testing is commonly used to determine the muscular strength of older individuals participating in a resistance training program. The purpose of this study was to non-invasively examine and compare the blood pressure (BP) and heart rate (HR) response of maximum and sub-maximum strength tests in older men. Twenty-four healthy men aged 70-80 yr were recruited for the study. Participants completed a 1 repetition maximum (RM) strength test and four days later a sub-maximum strength test on an incline squat. Systolic blood pressure (SBP), diastolic blood pressure (DBP) and HR were measured by plethysmography during and immediately after the strength tests. SBP, DBP and HR were (P<0.001) higher during the 1RM and sub-maximum strength tests compared to resting values. Twenty seconds post 1RM, SBP and HR were higher than resting values. Twenty seconds post sub-maximum strength testing SBP and DBP were lower (P<0.02) and HR (P<0.001) was higher than resting values. SBP, DBP and HR were higher (P<0.001) during sub-maximum strength testing compared to 1RM testing. Twenty seconds post testing, SBP and DBP were lower (P<0.001) and HR was higher (P<0.001) for the sub-maximum strength tests compared to the 1RM. The results of our study demonstrate that sub-maximum strength testing resulted in greater changes in BP and HR compared to 1RM strength testing. The lower cardiovascular stress experienced during the 1RM shows that this may be a safer method of testing compared to sub-maximum strength testing in men aged 70-80 yr.

The role of rate of force development on vertical jump performance.

The purpose of this study was to examine a) the relationship between rate of force development (RFD) and vertical jump (VJ) performance during a counter movement jump (CMJ), and b) the reliability of RFD recorded during the CMJ and squat jump (SJ) forms of the VJ. Twenty-three physically active men aged 23 ± 3.9 years participated in the study. Subjects completed 3 unloaded CMJ and 3 unloaded SJ in random order on a force plate. The RFD was measured during CMJ and SJ movements with vertical jump displacement (VJD) measured simultaneously during the CMJ only. Subjects incorporated arm swing to their CMJ technique to reach up as high as possible, and VJD was measured. All SJ were executed with both hands on the hips throughout the full range of movement. Peak rate of force development (PRFD), peak force (PF), and time to peak force (TPF) were significantly correlated to VJD during the CMJ (r = 0.68, r = 0.51, and r = -0.48, respectively). The RFD and TPF during the CMJ and SJ were associated with low test-retest reliability (coefficient of variation [CV]: 11.8-7.9%). Peak and average power, PF, and VJD produced high test-retest reliability (CV: 2.8-5.1%) during both the CMJ and SJ movements. Our results indicate that PRFD, a measure of explosive strength, and PF, a measure of maximal strength, are the primary contributors to VJD during the CMJ in physically active men. However, caution must be used when interpreting data using PRFD because of its low retest reliability.

Markers of postmatch fatigue in professional Rugby League players.

The aim of the present study was to identify neuromuscular, biochemical, and endocrine markers of fatigue after Rugby League match play. Seventeen elite Rugby League players were monitored for a single match. Peak rate of force development (PRFD), peak power (PP), and peak force (PF) were measured during a countermovement jump (CMJ) on a force plate pre and postmatch play. Saliva and blood samples were collected 24 hours prematch, 30 minutes prematch, 30 minutes postmatch, and then at 24-hour intervals for a period of 120 hours to determine plasma creatine kinase concentration ([CK]) and salivary cortisol concentration ([sCort]). There were significant (p < 0.05) decreases in PRFD and PP up to 24 hours postmatch with PF significantly (p < 0.05) decreased immediately postmatch. The [sCort] significantly (p < 0.05) increased from 24 hours prematch to 30 minutes prematch and up to 24 hours postmatch compared with 24 hours prematch. Plasma [CK] significantly (p < 0.05) increased 30 minutes postmatch with a peak occurring 24 hours postmatch and remained elevated above 24 hours prematch for at least 120 hours postmatch. There were significant (p < 0.05) correlations between the increase in [CK] and reduction in PRFD 30 minutes postmatch and 24 hours postmatch. The [sCort] was significantly (p < 0.05) correlated with the reduction in PF 30 minutes postmatch. Results demonstrate that neuromuscular function is compromised for up to 48 hours after match play. Elevated [CK] despite 120-hour recovery indicate that damage to muscle tissue after Rugby League match play may persist for at least 5 days postmatch. Despite the prolonged presence of elevated [CK] postmatch, strength training 48 hours postmatch may have resulted in a compensatory increase in PRFD supporting the inclusion of strength training during the short-term postmatch recovery period.

Creatine kinase and endocrine responses of elite players pre, during, and post rugby league match play.

The purpose of the present study was to (a) examine player-movement patterns to determine total distance covered during competitive Rugby League match play using global positioning systems (GPSs) and (b) examine pre, during, and postmatch creatine kinase (CK) and endocrine responses to competitive Rugby League match play. Seventeen elite rugby league players were monitored for a single game. Player movement patterns were recorded using portable GPS units (SPI-Pro, GPSports, Canberra, Australia). Saliva and blood samples were collected 24 hours prematch, 30 minutes prematch, 30 minutes postmatch, and then at 24-hour intervals for a period of 5 days postmatch to determine plasma CK and salivary testosterone, cortisol, and testosterone:cortisol ratio (T:C). The change in the dependent variables at each sample collection time was compared to 24-hour prematch measures. Backs and forwards traveled distances 5,747 ± 1,095 and 4,774 ± 1,186 m, respectively, throughout the match. Cortisol and CK increased significantly (p < 0.05) from 30 minutes prematch to 30 minutes postmatch. Creatine kinase increased significantly (p < 0.05) postmatch, with peak CK concentration measured 24 hours postmatch (889.25 ± 238.27 U·L). Cortisol displayed a clear pattern of response with significant (p < 0.05) elevations up to 24 hours postmatch, compared with 24 hours prematch. The GPS was able to successfully provide data on player-movement patterns during competitive rugby league match play. The CK and endocrine profile identified acute muscle damage and a catabolic state associated with Rugby League match play. A return to normal T:C within 48 hours postmatch indicates that a minimum period of 48 hours is required for endocrine homeostasis postcompetition. Creatine kinase remained elevated despite 120 hours of recovery postmatch identifying that a prolonged period of at least 5 days modified activity is required to achieve full recovery after muscle damage during competitive Rugby League match play.

The effect of strength training and short-term detraining on maximum force and the rate of force development of older men.

This study examined the effect of strength training (ST) and short-term detraining on maximum force and rate of force development (RFD) in previously sedentary, healthy older men. Twenty-four older men (70-80 years) were randomly assigned to a ST group (n = 12) and C group (control, n = 12). Training consisted of three sets of six to ten repetitions on an incline squat at 70-90% of one repetition maximum three times per week for 16 weeks followed by 4 weeks of detraining. Regional muscle mass was assessed before and after training by dual-energy X-ray absorptiometry. Training increased RFD, maximum bilateral isometric force, and force in 500 ms, upper leg muscle mass and strength above pre-training values (14, 25, 22, 7, 90%, respectively; P < 0.05). After 4 weeks detraining all neuromuscular variables were significantly (P < 0.05) lower than after 16 weeks training but remained significantly (P < 0.05) higher than pre-training levels except for RFD which had returned to pre-training levels. These findings demonstrate that high-intensity ST can improve maximum force and RFD of older men. However, older individuals may lose some neuromuscular performance after a period of short-term detraining and that resistance exercise should be performed on a regular basis to maintain training adaptations.

Can aerobic training improve muscle strength and power in older men?

This study examined the effect of aerobic training on leg strength, power, and muscle mass in previously sedentary, healthy older men (70-80 yr). Training consisted of 30-45 min of cycle ergometry at 50-70% maximal oxygen consumption (VO2max), 3 times weekly for 16 wk, then 4 wk detraining, or assignment to a nontraining control group (n = 12 both groups). Training increased leg strength, leg power, upper leg muscle mass, and VO2max above pretraining values (21%, 12%, 4%, and 15%, respectively; p < .05). However, all gains were lost after detraining, except for some gain in VO2max. This suggests that cycle ergometry is sufficient stimulus to improve neuromuscular function in older men, but gains are quickly lost with detraining. For the older population cycle ergometry provides the means to not only increase aerobic fitness but also increase leg strength and power and upper leg muscle mass. However, during periods of inactivity neuromuscular gains are quickly lost.

Resistance training reduces the blood pressure response of older men during submaximum aerobic exercise.

OBJECTIVE: The objective of this study was to determine whether 16 weeks of resistance training (RT) can reduce the blood pressure response and improve the cardiovascular function of men aged 70-80 years during submaximum aerobic exercise. METHODS: Twenty-four men aged between 70 and 80 years were randomly assigned to an RT group (n = 12) and control group (n = 12). Training consisted of three sets of six to 10 repetitions at 70-90% of one repetition maximum, three times per week, on an incline squat machine for 16 weeks. Blood pressure and cardiovascular function were assessed during submaximum cycle exercise at 40 W, and 50 and 70% of maximum oxygen consumption (VO2max) before training and after 16 weeks of training. Leg strength and VO2max were assessed every 4 weeks of the 16-week study. RESULTS: At 40 W, heart rate, systolic blood pressure, and rate pressure product were lower and stroke volume was significantly higher after 16 weeks of training. At 50% VO2max, heart rate and rate pressure product were lower after 16 weeks of training and at 70% VO2max, cycle ergometry power, VO2, and arterio-venous oxygen difference were higher after 16 weeks of training. Leg strength significantly increased after 16 weeks of training. CONCLUSION: Sixteen weeks of RT significantly reduces the blood pressure response and improves the cardiovascular function of older men during submaximum aerobic exercise. Therefore, RT not only increases muscular strength and hypertrophy but also provides significant cardiovascular benefits for older individuals.

Strength training improves submaximum cardiovascular performance in older men.

PURPOSE: To determine if 16 weeks of strength training can improve the cardiovascular function of older men during submaximum aerobic exercise. METHODS: Twenty four men aged 70-80 yr were randomly assigned to a strength training (ST; n = 12) and control group (C; n = 12). Training consisted of 3 sets of 6 - 10 repetitions at 70% to 90% of 1RM, 3 times per week, on an incline squat machine for 16 weeks, followed by 4 weeks detraining. Leg strength and maximum oxygen consumption (VO2 max) were assessed every 4 weeks of the 20-week study. Cardiovascular function was assessed during submaximum cycle exercise at 40 Watts, 50% and 70% of VO2 max before training, after 16 weeks training, and after 4 weeks detraining. RESULTS: At 40 Watts, heart rate (HR), systolic blood pressure, and rate pressure product (RPP) were lower and stroke volume (SV) significantly higher after 16 weeks training and 4 weeks detraining: at 50% VO2 max, HR and RPP were lower after 16 weeks training and 4 weeks detraining: at 70% VO2 max, cycle ergometry power, VO2 and arterio-venous oxygen difference (a - vO2 ) were higher after 16 weeks training. Leg strength and VO2 max increased after 16 weeks training, with leg strength remaining above pre-training levels after 4-weeks detraining. CONCLUSIONS: Sixteen weeks of strength training significantly improves the cardiovascular function of older men. Therefore strength training not only increases muscular strength and hypertrophy but also provides significant cardiovascular benefits for older individuals.