دانشکده دانشکده علوم ورزشی | سامانه جامع پژوهشی دانشگاه اصفهان

Objective: To assess the exposure of players to injury risk during English Premier League soccer matches in relation to selected factors. Methods: Injury risk was assessed by rating the injury potential of playing actions during competition with respect to (a) type of playing action, (b) period of the game, (c) zone of the pitch, and (d) playing either at home or away. In all, 10 games from the English Premier League 1999-2000 were chosen for analysis. A notation system was used whereby 16 soccer specific playing actions were classified into three categories: those inducing actual injury, those with a potential for injury (graded as mild, moderate, or high), and those deemed to have no potential for injury. The pitch was divided into 18 zones, and the position of each event was recorded along with time elapsed in the game, enabling six 15 minute periods to be defined. Results: Close to 18 000 actions were notated. On average (mean (SD)), 1788 (73) events (one every three seconds), 767 (99) events with injury potential (one every six seconds), and 2 (1) injuries (one every 45 minutes) per game were recorded. An overall injury incidence of 53 per 1000 playing hours was calculated. Receiving a tackle, receiving a "charge", and making a tackle were categorised as having a substantial injury risk, and goal catch, goal punch, kicking the ball, shot on goal, set kick, and heading the ball were all categorised as having a significant injury risk. All other actions were deemed low in risk. The first 15 minutes of each half contained the highest number of actions with mild injury potential, the last 15 minutes having the highest number of actions with moderate injury potential (p<0.01). The first and last 15 minutes of the game had the highest number of actions with high injury potential, although not significant. More actions with mild injury potential occurred in the goal area, and more actions with moderate and high injury potential occurred in the zone adjacent to the goal area (p<0.001). There was no significant difference between home and away with regard to injury potential. Conclusions: Playing actions with high injury risk were linked to contesting possession. Injury risk was highest in the first and last 15 minutes of the game, reflecting the intense engagements in the opening period and the possible effect of fatigue in the closing period. Injury risk was concentrated in the areas of the pitch where possession of the ball is most vigorously contested, which were specific attacking and defending zones close to the goal. Injury potential was no greater in away matches than at home.

2003

Interaction effects of time of day and menstrual cycle on muscle strength

( Article . )

Rahnama, N., Reilly, T., Lees, A., Graham-smith p.,

Publication Date: 2003

2025 29th International Computer Conference, Computer Society of Iran, CSICC 2025pp. 227-239

Muscle fatigue induced by exercise simulating the work rate of competitive soccer

( Article . Green )

Rahnama, N., Reilly, T., Lees, A., Graham-smith p.,

Publication Date: 2003

Journal of Sports Sciences (1466447X)21(11)pp. 933-942

Fatigue represents a reduction in the capability of muscle to generate force. The aim of the present study was to establish the effects of exercise that simulates the work rate of competitive soccer players on the strength of the knee extensors and knee flexors. Thirteen amateur soccer players (age 23.3 ± 3.9 years, height 1.78 ± 0.05 m, body mass 74.8±3.6 kg; mean ± s) were tested during the 2000-2001 soccer season. Muscle strength of die quadriceps and hamstrings was measured on an isokinetic dynamometer. A 90 min soccer-specific intermittent exercise protocol, incorporating a 15 min half-time intermission, was developed to provide fatiguing exercise corresponding in work rate to a game of soccer. The exercise protocol, performed on a programmable motorized treadmill, consisted of the different intensities observed during soccer match-play (e.g. walking, jogging, running, sprinting). Muscle strength was assessed before exercise, at half-time and immediately after exercise. A repeated-measures analysis of variance showed significant reductions (P < 0.001) in peak torque for both the quadriceps and hamstrings at all angular velocities (concentric: 1.05, 2.09, 5.23 rad.s-1; eccentric: 2.09 rad.s-1). The peak torque of the knee extensors (KE) and knee flexors (KF) was greater before exercise [KE: 232±37, 182±34, 129±27, 219±41 N.m at 1.05, 2.09 and 5.23 rad.s-1 (concentric) and 2.09 rad.s-1 (eccentric), respectively; KF: 126±20, 112±19, 101±16, 137±23 N.m] than at half-time (KE: 209±45, 177±35, 125±36, 214±43 N.m; KF: 114±31, 102±20, 92±15, 125±25 N.m) and greater at half-time than after exercise (KE: 196±43, 167±35, 118±24, 204±43 N.m; KF: 104±25, 95±21, 87±13, 114±27 N.m). For the hamstrings: quadriceps ratio, significant changes were found (P<0.05) for both legs, the ratio being greater before than after exercise. For fast:slow speed and left:right ratios, no significant changes were found. We conclude that there is a progressive reduction in muscle strength that applies across a range of functional characteristics during exercise that mimics the work rate in soccer.

2004

An analysis of injury risk in the Manchester united team when playing at home and away

( Article )

Rahnama, N., Reilly, T., Lees, A.

Publication Date: 2004

Cellular and Molecular Biology Letters (16891392)9(4 A)pp. 773-775

2005

A comparison of muscle strength and flexibility between the preferred and non-preferred leg in English soccer players

( Article . )

Rahnama, N., Lees, A., Bambaecichi, E.

Publication Date: 2005

Ergonomics (00140139)48(11-14)pp. 1568-1575

2006

Electromyography of selected lower-limb muscles fatigued by exercise at the intensity of soccer match-play

( Article . )

Rahnama, N., Lees, A., Reilly, T.

Publication Date: 2006

Journal of Electromyography and Kinesiology (18735711)16(3)pp. 257-263

2007

A practice-specificity-based model of arousal for achieving peak performance

( Article . )

Movahedi, A., Sheikh, M., Bagherzadeh, F., Hemayattalab, R., Ashayeri, H.

Publication Date: 2007

Journal of Motor Behavior (00222895)39(6)pp. 457-462

Manipulating high-intensity interval training: Effects on over(V, ̇) O2 max, the lactate threshold and 3000 m running performance in moderately trained males

( Article . )

Esfarjani, F., Laursen, P.B.

Publication Date: 2007

Journal of Science and Medicine in Sport (14402440)10(1)pp. 27-35

The aim of this study was to compare the effects of two high-intensity interval training (HIT) programmes on maximal oxygen uptake (over(V, ̇) O2 max), the lactate threshold (LT) and 3000 m running performance in moderately trained male runners. over(V, ̇) O2max, the running speed associated with over(V, ̇) O2max (vover(V, ̇) O2 max), the time for which vover(V, ̇) O2 max can be maintained (Tmax), the running speed at LT (vLT) and 3000 m running time (3000mTT) were determined before and following three different training programmes performed for 10 weeks. Following the pre-test, 17 moderately trained male runners (over(V, ̇) O2max = 51.6 ± 2.7 ml k g- 1 mi n- 1) were divided into training groups based on their 3000mTT (Group 1, G1, N = 6, 8× 60% of Tmax at vover(V,̇) O2 max, 1:1 work:recovery ratio; Group 2, G2, N = 6, 12× 30s at 130% vover(V, ̇) O2max, 4.5 min recovery; control group, GCON, N = 5, 60 min at 75% vover(V, ̇) O2 max). G1 and G2 performed two HIT sessions and two 60 min recovery run sessions (75% vover(V, ̇) O2max) each week. Control subjects performed four 60 min recovery run sessions (75% vover(V, ̇) O2 max) each week. In G1, significant improvements (p < 0.05) following HIT were found in over(V, ̇) O2 max (+9.1%), vover(V, ̇) O2 max (+6.4%), Tmax (5%), vLT (+11.7%) and 3000mTT (-7.3%). In G2, significant improvements (p < 0.05) following HIT were found in over(V, ̇) O2 max (+6.2%), vover(V, ̇) O2max (+7.8%), Tmax (+32%) and 3000mTT (-3.4%), but not in vLT (+4.7%; p = 0.07). No significant changes in these variables were found in GCON. The present study has shown that 3000 m running performance, over(V, ̇) O2 max, vover(V, ̇) O2 max, Tmax and vLT can be significantly enhanced using different HIT programmes in moderately trained runners, but that changes in performance and physiological variables may be more profound using prolonged HIT at intensities of vover(V, ̇) O2max with interval durations of 60% Tmax. © 2006 Sports Medicine Australia.