Current Soccer Footwear, Its Role in Injuries and Potential for Improvement

Sylvain Blanchard; Jérôme Palestri; Jean-Luc Guer; Michel BEHR

doi:10.1055/a-0608-4229

Sports Medicine International Open, Table of Contents

CC BY-NC-ND 4.0 · Sports Med Int Open 2018; 02(02): E52-E61
DOI: 10.1055/a-0608-4229

Review

Current Soccer Footwear, Its Role in Injuries and Potential for Improvement

Authors

Sylvain Blanchard

¹Laboratoire de Biomécanique Appliquée, Aix-Marseille Univ, IFSTTAR, LBA UMR_T24, Marseille, France
Jérôme Palestri

²Wizwedge SARL, Research Department, Marseille, France
Jean-Luc Guer

²Wizwedge SARL, Research Department, Marseille, France
Michel BEHR

¹Laboratoire de Biomécanique Appliquée, Aix-Marseille Univ, IFSTTAR, LBA UMR_T24, Marseille, France

Abstract

Soccer is the most popular sport in the world and generates great financial revenue. It is also a sport whose practice has evolved considerably in terms of intensity and commitment, and in which the intrinsic risk of injury (not directly related to an interaction with the environment) is particularly high. In this context, the cleated shoe as a major component of soccer equipment may play a key role in the overexposure to injury. Soccer shoe evolution is all the more challenging, because design and mechanical structure differ in many points compared to other modern shoes developed for sports such as running, tennis and basketball.

This critical review aims to elucidate the characteristics of modern soccer footwear and their possible link to soccer-specific injuries, focusing on the following areas: (1) ergonomics, comfort and proprioception; (2) shoe mechanical characteristics; (3) field surfaces and shoe design.

Key words

sports medicine - athletic injuries - biomechanics - footwear

Full Text

References

References
1 Alfredson H, Cook J. A treatment algorithm for managing Achilles tendinopathy: New treatment options. Br J Sports Med 2007; 41: 211-216
2 Allard P, Bianchi JP. Analyse du mouvement humain par la biomécanique. Mont-Royal: Décarie Editeur Inc; 1996
3 Amos M, Morag E. Effect of shoe mass on soccer kicking velocity. Proceedings of the Fourth World Congress of Biomechanics. Calgary: Omnipress; 2002
4 Baldassin V, Gomes CR, Beraldo PS. Effectiveness of prefabricated and customized foot orthoses made from low-cost foam for noncomplicated plantar fasciitis: A randomized controlled trial. Arch Phys Med Rehabil 2009; 90: 701-706
5 Barker HB, Beynnon BD, Renström PA. Ankle injury risk factors in sports. Sports Med 1997; 23: 69-74
6 Barrett JR, Tanji JL, Drake C, Fuller D, Kawasaki RI, Fenton RM. High- versus low-top shoes for the prevention of ankle sprains in basketball players. A prospective randomized study. Am J Sports Med 1993; 21: 582-585
7 Becerro-de-Bengoa-Vallejo R, Losa-Iglesias ME, Rodriguez-Sanz D. Static and dynamic plantar pressures in children with and without Sever disease: A case-control study. Phys Ther 2014; 94: 818-826
8 Bentley JA, Ramanathan AK, Arnold GP, Wang W, Abboud RJ. Harmful cleats of football boots: A biomechanical evaluation. Foot Ankle Surg 2011; 17: 140-144
9 Bere T, Flørenes TW, Krosshaug T, Koga H, Nordsletten L, Irving C, Bahr R. Mechanisms of anterior cruciate ligament injury in World Cup alpine skiing: A systematic video analysis of 20 cases. Am J Sports Med 2011; 39: 1421-1429
10 Boden BP, Torg JS, Knowles SB, Hewett TE. Video analysis of anterior cruciate ligament injury: Abnormalities in hip and ankle kinematics. Am J Sports Med 2009; 37: 252-259
11 Boling MC, Padua DA, Marshall SW, Guskiewicz K, Pyne S, Beutler A. A prospective investigation of biomechanical risk factors for patellofemoral pain syndrome: The Joint Undertaking to Monitor and Prevent ACL Injury (JUMP-ACL) cohort. Am J Sports Med 2009; 37: 2108-2116
12 Bonanno DR, Landorf KB, Menz HB. Pressure-relieving properties of various shoe inserts in older people with plantar heel pain. Gait Posture 2011; 33: 385-389
13 Che H, Nigg BM, de Koning J. Relationship between plantar pressure distribution under the foot and insole comfort. Clin Biomech 1994; 9: 335-341
14 Chen TH, Chou LW, Tsai MW, Lo MJ, Kao MJ. Effectiveness of a heel cup with an arch support insole on the standing balance of the elderly. Clin Interv Aging 2014; 9: 351-356
15 Chew-Bullock TS, Anderson DI, Hamel KA, Gorelick ML, Wallace SA, Sidaway B. Kicking performance in relation to balance ability over the support leg. Hum Mov Sci 2012; 31: 1615-1623
16 Clarke JD, Carré MJ. Improving the performance of soccer boots on artificial and natural soccer surfaces. Procedia Eng 2010; 2: 2775-2781
17 Cortes N, Morrison S, Van Lunen BL, Onate JA. Landing technique affects knee loading and position during athletic tasks. J Sci Med Sport 2012; 15: 175-181
18 Coyles VR, Lake ML. Forefoot plantar pressure distribution inside the soccer boot during running. Research Institute for Sport and Exercise Science 1999. UK: Liverpool John Moores University;
19 De Castro MP, Meucci M, Soares DP, Fonseca P, Borgonovo-Santos M, Sousa F, Vilas-Boas JP. Accuracy and repeatability of the gait analysis by the WalkinSense system. Biomed Res Int 2014; 348659
20 De Noronha M, França LC, Haupenthal A, Nunes GS. Intrinsic predictive factors for ankle sprain in active university students: A prospective study. Scand J Med Sci Sports 2013; 23: 541-547
21 De Wit B, De Clercq D, Aerts P. Ground reaction forces and spatio-temporal variables during barefoot and shod running. In: Abrantes J. ed.), Proceedings of the XIVth symposium on biomechanics in sports. 1996: 252-255
22 De Wit B, De Clercq D, Aerts P. Biomechanical analysis of the stance phase during barefoot and shod running. J Biomech 2000; 13: 269-278
23 Debiasio J, Russell M, Butler R, Nunley J, Queen R. Changes in plantar loading based on shoe type and sex during a jump-landing task. J Athl Train 2013; 48: 601-609
24 Divert C, Mornieux G, Baur H, Mayer F, Belli A. Mechanical comparison of barefoot and shod running. Int J Sports Med 2005; 26: 593-598
25 Drakos MC, Hillstrom H, Voos JE, Miller AN, Kraszewski AP, Wickiewicz TL, O'Brien SJ. The effect of the shoe-surface interface in the development of anterior cruciate ligament strain. J Biomech Eng 2010; 132: 011003
26 Dueñas L, Ferrandis R, Martinez A, Candel J, Arnau F, Villanueva J. Application of biomechanics to the prevention of overload injuries in elite soccer players. In: Gianikellis KE. ed.), Proceedings of the XXth Symposium on Biomechanics in Sports. Cácares: 2002: 585-588
27 Eils E, Streyl M, Linnenbecker S, Thorwesten L, Völker K, Rosenbaum D. Characteristic plantar pressure distribution patterns during soccer-specific movements. Am J Sports Med 2004; 32: 140-145
28 Ekstrand J, Hägglund M, Kristenson K, Magnusson H, Waldén M. Fewer ligament injuries but no preventive effect on muscle injuries and severe injuries: An 11-year follow-up of the UEFA Champions League injury study. Br J Sports Med 2013; 47: 732-737
29 Ekstrand J, Hägglund M, Waldén M. Injury incidence and injury patterns in professional football: The UEFA injury study. Br J Sports Med 2011; 45: 553-558
30 Ferran NA, Maffulli N. Epidemiology of sprains of the lateral ankle ligament complex. Foot Ankle Clin 2006; 11: 659-662
31 Fong CM, Blackburn JT, Norcross MF, McGrath M, Padua DA. Ankle-dorsiflexion range of motion and landing biomechanics. J Athl Train 2011; 46: 5-10
32 Fong DT, Chan YY, Mok KM, Yung PS, Chan KM. Understanding acute ankle ligamentous sprain injury in sports. Sports Med Arthrosc Rehabil Ther Technol 2009; 1: 14
33 Ford KR, Manson NA, Evans BJ, Myer GD, Gwin RC, Heidt RS, Hewett TE. Comparison of in-shoe foot loading patterns on natural grass and synthetic turf. J Sci Med Sport 2006; 9: 433-440
34 Franz JR, Wierzbinski CM, Kram R. Metabolic cost of running barefoot versus shod: Is lighter better?. Med Sci Sports Exerc 2012; 44: 1519-1525
35 Frederick EC. Physiological and ergonomics factors in running shoe design. Appl Ergon 1984; 15: 281-287
36 Fu W, Fang Y, Liu Y, Hou J. The effect of high-top and low-top shoes on ankle inversion kinematics and muscle activation in landing on a tilted surface. J Foot Ankle Res 2014; 7: 14
37 Galbusera F, Tornese DZ, Anasetti F, Bersini S, Volpi P, La Barbera L, Villa T. Does soccer cleat design influence the rotational interaction with the playing surface?. Sports Biomech 2013; 12: 293-301
38 Giannini S, Buda R, Mosca M, Parma A, Di Caprio F. Posterior ankle impingement. Foot Ankle Int 2013; 34: 459-465
39 Gutierrez GM, Jackson ND, Dorr KA, Margiotta SE, Kaminski TW. Effect of fatigue on neuromuscular function at the ankle. J Sport Rehabil 2007; 16: 295-306
40 Handoll HH, Rowe BH, Quinn KM, De Bie R. Withdrawn: Interventions for preventing ankle ligament injuries. Cochrane Database Syst Rev 2011; 5: CD000018
41 Hennig EM. Plantar pressure measurements for the evaluation of shoe comfort, overuse injuries and performance in soccer. Footwear science 2014; 6: 119-127
42 Hennig EM. The influence of soccer shoe design on player performance and injuries. Res Sports Med 2011; 19: 186-201
43 Hennig EM, Sterzing T. The influence of soccer shoe design on playing performance–a series of biomechanical studies. Footwear Sci 2010; 2: 3-11
44 Hennig EM, Sterzing T. Special Issue: Soccer shoes: Enhancing fit and performance. Footwear Sci 2014; 67-68
45 Hinz P, Henningsen A, Matthes G, Jäger B, Ekkernkamp A, Rosenbaum D. Analysis of pressure distribution below the metatarsals with different insoles in combat boots of the German Army for prevention of march fractures. Gait Posture 2008; 27: 535-538
46 Hreljac A, Marshall RN, Hume PA. Evaluation of lower extremity overuse injury potential in runners. Med Sci Sports Exerc 2000; 32: 1635-1641
47 Hägglund M, Waldén M, Ekstrand J. UEFA injury study–an injury audit of European Championships 2006 to 2008. Br J Sports Med 2009; 43: 483-489
48 Johanson MA, Cooksey A, Hillier C, Kobbeman H, Stambaugh A. Heel lifts and the stance phase of gait in subjects with limited ankle dorsiflexion. J Athl Train 2006; 41: 159-165
49 Johnson GR, Dowson D, Wright V. A biomechanical approach to the design of football boots. J Biomech 1976; 9: 581-585
50 Jordan C, Payton C, Bartlett R. Perceived comfort and pressure distribution in casual footwear. Clin Biomech 1997; 12: S5
51 Kapandji AI. Anatomie fonctionnelle T.2–Membre inférieur. 6ème édition , Paris: Maloine; 2009
52 Kaufman KR, Brodine SK, Shaffer RA, Johnson CW, Cullison TR. The effect of foot structure and range of motion on musculoskeletal overuse injuries. Am J Sports Med 1999; 27: 585-593
53 Kavanaugh JH, Brower TD, Mann RV. The Jones fracture revisited. J Bone Joint Surg Am 1978; 60: 776-782
54 Kerr R, Arnold GP, Drew TS, Cochrane LA, Abboud RJ. Shoes influence lower limb muscle activity and may predispose the wearer to lateral ankle ligament injury. J Orthop Res 2009; 27: 318-324
55 Kibler WB, Goldberg C, Chandler TJ. Functional biomechanical deficits in running athletes with plantar fasciitis. Am J Sports Med 1991; 19: 66-71
56 Kinchington M, Ball K, Naughton G. Monitoring of lower limb comfort and injury in elite football. J Sports Sci Med 2010; 9: 652-663
57 Kinchington M, Ball K, Naughton G. Relation between lower limb comfort and performance in elite footballers. Phys Ther Sport 2012; 13: 27-34
58 Kinchington M, Ball K, Naughton G. Effects of footwear on comfort and injury in professional rugby league. J Sports Sci 2011; 29: 1407-1415
59 Kirk RF, Noble ISG, Miychell T, Rolf C, Haake SJ, Carré ML. High speed evaluation of football-boot-surface interactions of players in their natural environment. Sports Eng 2007; 10: 123-144
60 Klein C, Groll-Knapp E, Kundi M, Kinz W. Increased hallux angle in children and its association with insufficient length of footwear: A community based cross-sectional study. BMC Musculoskelet Disord 2009; 10: 159
61 Knight AC, Weimar WH. Effects of inversion perturbation after step down on the latency of the peroneus longus and peroneus brevis. J Appl Biomech 2011; 27: 283-290
62 Kovács I, Tihanyi J, Devita P, Rácz L, Barrier J, Hortobágyi T. Foot placement modifies kinematics and kinetics during drop jumping. Med Sci Sports Exerc 1999; 31: 708-716
63 Lambson R, Barhnill B, Higgins R. Football cleat design and its effect on anterior cruciate ligament injuries – A three-year prospective study. Am J Sports Med 1996; 24: 155-159
64 Lanzetti RM, Ciompi A, Lupariello D, Guzzini M, De Carli A, Ferretti A. Safety of third-generation artificial turf in male elite professional soccer players in Italian major league. Scand J Med Sci Sports 2017; 27: 435-439
65 Lee SY, McKeon P, Hertel J. Does the use of orthoses improve self-reported pain and function measures in patients with plantar fasciitis? A meta-analysis. Phys Ther Sport 2009; 10: 12-18
66 Lee YC, Lin G, Wang MJ. Evaluating insole design with joint motion, plantar pressure and rating of perceived exertion measures. Work 2012; 41 (Suppl. 01) 1114-1117
67 Lees A, Kewley P. The demands on the soccer boot. Science and Football 1993; 2: 335-340
68 Lees A, Nolan L. The biomechanics of soccer: A review. J Sports Sci 1998; 16: 211-234
69 Lin CF, Gross ML, Weinhold P. Ankle syndesmosis injuries: Anatomy, biomechanics, mechanism of injury, and clinical guidelines for diagnosis and intervention. J Orthop Sports Phys Ther 2006; 36: 372-384
70 Malliaras P, Cook JL, Kent P. Reduced ankle dorsiflexion range may increase the risk of patellar tendon injury among volleyball players. J Sci Med Sport 2006; 9: 304-309
71 Mayer F, Hirschmüller A, Müller S, Schuberth M, Baur H. Effects of short-term treatment strategies over 4 weeks in Achilles tendinopathy. Br J Sports Med 2007; 41: e6
72 Messier SP, Davis SE, Curl WW, Lowery RB, Pack RJ. Etiologic factors associated with patellofemoral pain in runners. Med Sci Sports Exerc 1991; 23: 1008-1015
73 Milani TL, Hennig EM, Lafortune MA. Perceptual and biomechanical variables for running in identical shoe constructions with varying midsole hardness. Clin Biomech 1997; 12: 294-300
74 Milner CE, Ferber R, Pollard CD, Hamill J, Davis IS. Biomechanical factors associated with tibial stress fracture in female runners. Med Sci Sports Exerc 2006; 38: 323-328
75 Moschini A, Smith N. Effect of shoe mass on soccer kicking velocity. In: Bradshaw E, Burnett A. (eds.), Scientific Proceedings of the 30^th Annual Conference of Biomechanics in Sports. Melbourne: Australian Catholic University; 2012: 150-153
76 Mündermann A, Stefanyshyn DJ, Nigg BM. Relationship between footwear comfort of shoe inserts and anthropometric and sensory factors. Med Sci Sports Exerc 2001; 33: 1939-1945
77 Novacheck TF. The biomechanics of running. Gait Posture 1998; 7: 77-95
78 O'Connor AM, James IT. Association of lower limb injury with boot cleat design and playing surface in elite soccer. Foot Ankle Clin 2013; 18: 369-380
79 Peña FA, Coetzee JC. Ankle syndesmosis injuries. Foot Ankle Clin 2006; 11: 35-50
80 Perhamre S, Lundin F, Norlin R, Klässbo M. Sever's injury; treat it with a heel cup: A randomized, crossover study with two insole alternatives. Scand J Med Sci Sports 2011; 21: e42
81 Pohl MB, Hamill J, Davis IS. Biomechanical and anatomic factors associated with a history of plantar fasciitis in female runners. Clin J Sport Med 2009; 19: 372-376
82 Rabin A, Kozol Z, Finestone AS. Limited ankle dorsiflexion increases the risk for mid-portion Achilles tendinopathy in infantry recruits: A prospective cohort study. J Foot Ankle Res 2014; 7: 48
83 Ramanathan AK, John MC, Arnold GP, Cochrane L, Abboud RJ. The effects of off-the-shelf in-shoe heel inserts on forefoot plantar pressure. Gait Posture 2008; 28: 533-537
84 Ramanathan AK, Wallace DT, Arnold GP, Drew TS, Wang W, Abboud RJ. The effect of varying footwear configurations on the peroneus longus muscle function following inversion. Foot 2011; 21: 31-36
85 Riddle DL, Pulisic M, Pidcoe P, Johnson RE. Risk factors for plantar fasciitis: A matched case-control study. J Bone Joint Surg Am 2003; 85: 872-877
86 Rovere GD, Clarke TJ, Yates CS, Burley K. Retrospective comparison of taping and ankle stabilizers in preventing ankle injuries. Am J Sports Med 1998; 16: 228-233
87 Ryan M, Elashi M, Newsham-West R, Taunton J. Examining injury risk and pain perception in runners using minimalist footwear. Br J Sports Med 2014; 48: 1257-1262
88 Ryan M, Grau S, Krauss I, Maiwald C, Taunton J, Horstmann T. Kinematic analysis of runners with achilles mid-portion tendinopathy. Foot Ankle Int 2009; 30: 1190-1195
89 Santos D, Carline T, Flynn L, Pitman D, Feeney D, Patterson C, Westland E. Distribution of in-shoe dynamic plantar foot pressures in professional football players. The Foot 2001; 11: 10-14
90 Sarcević Z. Limited ankle dorsiflexion: A predisposing factor to Morbus Osgood Schlatter?. Knee Surg Sports Traumatol Arthrosc 2008; 16: 726-728
91 Saunders PU, Pyne DB, Telford RD, Hawley JA. Factors affecting running economy in trained distance runners. Sports Med 2004; 34: 465-485
92 Seligman DA, Dawson DR. Customized heel pads and soft orthotics to treat heel pain and plantar fasciitis. Arch Phys Med Rehabil 2003; 84: 1564-1567
93 Shorten MR. Running shoe design: protection and performance. In: Tunstall Pedoe D. ed. Marathon Medicine. London: Royal Society of Medicine; 2000: 159-169
94 Shuen WM, Boulton C, Batt ME, Moran C. Metatarsal fractures and sports. Surgeon 2009; 7: 86-88
95 Shultz SJ, Nguyen AD, Levine BJ. The relationship between lower extremity alignment characteristics and anterior knee joint laxity. Sports Health 2009; 1: 54-60
96 Sims EL, Hardaker WM, Queen RM. Gender differences in plantar loading during three soccer-specific tasks. Br J Sports Med 2008; 42: 272-277
97 Slade SJ, Greenya JG, Kliethermes CL, Senchina DS. Somatosensory perception of running shoe mass. Ergonomics 2014; 57: 912-920
98 Smeets K, Jacobs P, Hertogs R, Luyckx JP, Innocenti B, Corten K, Bellemans J. Torsional injuries of the lower limb: An analysis of the frictional torque between different types of football turf and the shoe outsole. Br J Sports Med 2012; 46: 1078-1083
99 Sterzing T. Actual and perceived running performance in soccer shoes: A series of eight studies. Footwear Sci 2009; 1: 5-19
100 Sterzing T, Henning EM. The influence of soccer shoe on kicking velocity in full-instep kicks. Exerc Sport Sci Rev 2008; 36: 91-97
101 Tabrizi P, McIntyre WM, Quesnel MB, Howard AW. Limited dorsiflexion predisposes to injuries of the ankle in children. J Bone Joint Surg Br 2000; 82: 1103-1106
102 Tol JL, Slim E, Van Soest AJ, Van Dijk CN. The relationship of the kicking action in soccer and anterior ankle impingement syndrome. A biomechanical analysis. Am J Sports Med 2002; 30: 45-50
103 Tol JL, Van Dijk CN. Etiology of the anterior ankle impingement syndrome: A descriptive anatomical study. Foot Ankle Int 2004; 25: 382-386
104 Tol JL, Van Dijk CN. Anterior ankle impingement. Foot Ankle Clin 2006; 11: 297-310
105 Tsintzas D, Ghosh S, Maffulli N, King JB, Padhiar N. The effect of ankle position on intracompartmental pressures of the leg. Acta Orthop Traumatol Turc 2009; 43: 42-48
106 Tung KD, Franz JR, Kram R. A test of the metabolic cost of cushioning hypothesis during unshod and shod running. Med Sci Sports Exerc 2014; 46: 324-329
107 Van Beijsterveldt AM, Krist MR, Schmikli SL, Stubbe JH, De Wit GA, Inklaar H, Backx FJ. Effectiveness and cost-effectiveness of an injury prevention programme for adult male amateur soccer players: Design of a cluster-randomised controlled trial. Inj Prev 2011; 17: e2
108 Vanore JV, Christensen JC, Kravitz SR, Schuberth JM, Thomas JL, Weil LS, Zlotoff HJ, Mendicino RW, Couture SD. Diagnosis and treatment of first metatarsophalangeal joint disorders. Section 2: Hallux rigidus. J Foot Ankle Surg 2003; 42: 124-136
109 Waddington G, Adams R. Discrimination of active plantarflexion and inversion movements after ankle injury. Aust J Physiother 1999; 45: 7-13
110 Waddington G, Adams R. Football boot insoles and sensitivity to extent of ankle inversion movement. Br J Sports Med 2003; 37: 170-175
111 Waddington G, Adams R. Textured insole effects on ankle movment discrimination while wearing athletic shoes. Physical Therapy in Sport 2000; 1: 129-136
112 Walter JH, Ng GK. Evaluation of cleated shoes with the adolescent athlete in soccer. The Foot 2002; 12: 158-165
113 Weinfeld SB, Haddad SL, Myerson MS. Metatarsal stress fractures. Clin Sports Med 1997; 16: 319-338
114 Werner RA, Gell N, Hartigan A, Wiggerman N, Keyserling WM. Risk factors for plantar fasciitis among assembly plant workers. PM R 2010; 2: 110-116
115 Wierzbinski CM. The separate effects of shoe mass and cushioning on the energetic cost of barefoot vs shod running [Thesis]. Boulder, Colorado: University of Colorado Boulder; 2011
116 Willems TM, Witvrouw E, Delbaere K, Mahieu N, De Bourdeaudhuij I, De Clercq D. Intrinsic risk factors for inversion ankle sprains in male subjects: A prospective study. Am J Sports Med 2005; 33: 415-423
117 Williams JH, Akogyrem E, Williams JR. A meta-analysis of soccer injuries on artificial turf and natural grass. J Sports Med 2013; 2013: 1-6
118 Wong PL, Chamari K, Chaouachi A, Mao DW, Wisløff U, Hong Y. Difference in plantar pressure between the preferred and non-preferred feet in four soccer-related movements. Br J Sports Med 2007; 41: 84-92
119 Wong PL, Chamari K, Chaouachi A, Mao DW, Wisløff U, Hong Y. Higher plantar pressure on the medial side in four soccer-related movements. Br J Sports Med 2007; 41: 93-100
120 Yamada RK, Arliani GG, Almeida GP, Venturine AM, Santos CV, Astur DC, Cohen M. The effects of one-half of a soccer match on the postural stability and functional capacity of the lower limbs in young soccer players. Clinics 2012; 67: 1361-1364
121 Yung-Hui L, Wei-Hsien H. Effects of shoe inserts and heel height on foot pressure, impact force, and perceived comfort during walking. Appl Ergon 2005; 36: 355-362
122 Zhang X, Li B. Influence of in-shoe heel lifts on plantar pressure and center of pressure in the medial-lateral direction during walking. Gait Posture 2014; 39: 1012-1016